Researched, Written, and Submitted by Enrico Ratti of Venice, Italy. 
Additional follow-up information provided by Enrico follows this article
Many Thanks Enrico!!!!!!!! 
The Ratti family name:
origins, history, and present status
by Enrico Ratti of Venice, Italy
(edited by J. Louis Ratti)
For the most part, people bearing the Ratti family name all over the world are originaly from Italy. The sole exceptions are few families original from Finland and from India.
The earliest occurrence of the Ratti family name is recorded from northwestern Italy: Piedmont (11th century) and Liguria (12th century).
Ethymology
According to Joseph G. Fucilla, an Italo-American researcher, the Ratti family name originated from the German, namely from the Christian name "Rad" or "Rat". In a similar way, the German Christian name "Conrad" originated the Italian "Corrado". In such case the name should have a patronimic origin, as the largest part of the family names, originating from the Christian name of the father of the original name-bearer. So, the meaning of the name should be "son of [Con]rad". The final letter "i" of the name Ratti indicates the plural form.
Personally, I disagree with this opinion, that could at most explain the origin of family names such as Rado, Raddo, Raddi, which are comparatively scarce in Italy.
Emidio De Felice , an Italian researcher, believes that the Ratti family name originated from the common name "rattus" (Latin), "ratto" (Italian), meaning rat. This word has been used as a nickname since long ago in Italy . In the popular culture, the rat is the symbol of readiness and cunning, and sometimes of cruelty. In the coat-of-arms of the noble Ratti family from Piacenza (Emily), as well as in that of the Rattazzi family from Alessandria (Piedmont), a black rat is represented.
Originally the name was present everywhere in both singular and plural form (Ratto and Ratti), with no distinction, even for the same individual. Later, some families became definitively Ratto, some others Ratti. Today are known also the derived forms Rattaro, Rattazzi, Rattazzo, Rattin, Rattini, Ratton and Rattone. Possibly also the French family names Ratté, Raté, and Rattie, are closely related to Ratti.
Origins
The Ratti family name is supposed - as mentioned above - to have its origin in northwestern Italy during the late Middle Ages, probably in different places nearly at the same time.
The main Ratti group, the most numerous, is original from an area including western Piedmont and Liguria in northwestern Italy. It is supported by documentary evidence at Mentone (Menton, presently France but formerly Italy) and Cuneo (Piedmont) in the 11th century, and in Liguria in 12th century. It is currently widespread in Italy, and also in several European countries, North and South America, Australia.
A second, minor Ratti group, is original from Premana (eastern Lombardy, north Italy) where it was recorded since the early 15th Century. It presently occurs only in Premana, Venice and Montevideo (Uruguay).
The Ratti family name occurs in Liguria, since the beginning, mostly in the singular form Ratto. Anyway, the two families (Ratto and Ratti), both with noble branches, apparently parted very early and are still divided at present time.
The coat-of-arms of the noble Ratto family from Genoa shows three golden stars on a light blue background. Currently, it mostly occurs in Liguria (fig. 1).
 
Fig. 1. Current distribution of the Ratto family name in Italy.
The main Ratti group divided during the Middle Ages into two major lineages: the Ratti Mentone and the Ratti Opizzone (or Oppizzone, or Oppizzoni). All further minor groups are probably derived from these two lineages.
The Ratti "Mentone" family
The earliest lineage is that of the Ratti from Northern Italy in the area of Cherasco (close to Cuneo, Piedmont).  It is an ancient family known since the 11th century, also called Ratti Mentone (from Menton, presently France) .
From this family probably descends the Ratti family from Desio (Milano): Achille Ratti (Pope Pius XI) is the most famous representative.
The coat-of-arms of the Ratti Mentone is illustrated in fig. 2; a variant in fig. 3. The motto was: Virtus beatos efficit (Boldness makes blissfulness). Oddino Ratti was Viceroy of Cuneo, 1364; the standard bearer Giovanni Matteo Ratti delivered the coat-of-arms 1614, March 4 .
Fig. 2-3. Coat-of-arms of the Ratti Mentone family (with a variant).
From Mentone  the family probably spread to Nizza (Nice, presently France but formerly Italy). Through the kindness of Mrs. Sheila Chapman , a descendant, I have some information on a Ratti family from Nice. The branch progenitor is Count Andrea Berengarius Ratti, father of Carolus Aloysius Ratti (Carlo, Charles): the latter was born in 1771, and had two sons: Joseph (1821-1897), Major General, ADC to King of Sicily, and François Ignace Charles (chevalier Francesco), 1827-1918, land owner. The Ratti family in Nice gave name to the Ratti Avenue and to Villa Ratti. The family migrated (in part) to England early in 1860.
A further noble lineage in Piedmont, of recent date but probably originated by the Ratti Mentone, is that of the Ratti Marquises of Torre Rossano. This family is original from Trino (Vercelli), then went to Cherasco. Domenico Ratti, surgeon in Trino, was father of the lawyer Marcello Ratti, judge in Cherasco, then major of Trino. Marcello married Maddalena Ratti, daughter of the noble Luigi Ratti. Their son Domenico Ratti, born in Trino, 1859, was senator of the Kingdom of Italy, appointed Count in 1887 and finally marquis of Torre Rossano (estate in the country of Cherasco) in 1892. Coat-of-arms as in fig. 4. Motto: "A buona speranza" (At good hope) .
 
The Ratti "Opizzone" family
The Ratti Opizzone family (or Ratti Oppizzoni, or Ratti Opizzoni), was recorded in Tortona (Alessandria, Piedmont) since 13th century. Main residences in Tortona, Torino and Reggio Emilia. Recorded in heraldry also as Opizzoni family from Milan. Livio de Ratti, consul, was recorded in 1221 . The Duke of Milan, 1413, May 24, enfeoffed the brothers Antonio and Giovanni Ratti Opizzoni with the dominion of Villa di Tozze, Castel de’ Ratti, Persio, Cerreto (currently Cerreto Ratti) and Liveto, localities in the territory of Borghetto di Borbera (Alessandria) .
A member of the Opizzoni family was counselor of a German emperor in 12th century. In the ancient German, counselor was "Rath": So that branch of the family was nicknamed "Rato", "Rati", "Ratti".
"Castel de’ Ratti" (Ratti Castle), in the lower Val Borbera, is of very ancient origin, built before 1155 . On the outer stony walls of the castle it is sculptured the family coat-of-arms. The family gave Knights of Malta and several famous persons: Carlo Alberto Ratti, valiant army leader, died in Flanders; Bernardo Ratti (1414 - 1477), professor of jurisprudence; Giovanni Parini Ratti (born 1515), soldier; Onorato Ratti Oppizzone (dead 1573), lawyer; Alberto Ratti Oppizzone (recorded 1602), Knight of Malta; Bernardo Ratti Oppizzone (recorded 1618), jurist; Antonio Ratti Oppizzone (recorded 1653), jurist and orator ; Carlo Ratti Oppizzone, cardinal (first half of 19th Century) . "Castello Torre Ratti" is today is an appreciated wine firm in Piedmont. In wine labels the coat-of-arms of the Ratti Opizzone family is evident (fig. 5). At the Annunziata Abbey (La Morra close to Alba, Piedmont), rises a "Ratti Museum of Alba wines", founded by Renato Ratti, famous oenologist and producer of vintage wines.
Fig. 5. Trade mark of the "Castello Torre Ratti", producer of vintage wines.
The family branch from Pavia (Lombardy) had the title of count of the Holy Roman Empire . Coat-of-arms as in fig. 6. Mottoes: Omnia cum tempore (All with time); Sub tuum praesidium (Under your protection) .
 
Fig. 6. Coat-of-arms of the Ratti Opizzone family.
Borgoratto Alessandrino, a village near Alessandria, is recorded as Burgorattus (1237), as Burgi Ratti (1290) and as Burgumrattum (1404). The name is composed by "borgo" (village) and Ratti, family once and also now living there .
The Ratti family from Desio (Milano) (the family of Ambrogio Damiano Achille Ratti, Pope Pius XI) according to some researchers, is related to the Ratti Counts of Cherasco. However, the coat-of-arms is, on the contrary, closely related to the Ratti Opizzone one: top, a blak eagle on a golden background; bottom, three red balls on a silver background. This family was recorded in Desio (Milano), and in Rogeno near Pieve di Fucino (Milano) since 1614 .
A part of the family followed Achille Ratti in Rome when he became Pope, and about 60 Ratti families currently live in Latium. Pope Achille Ratti appointed Count his nephew, Francesco Ratti. Anyway, the Ratti family is recorded in Latium at least since 18th century: in 1797 the abbot Nicola Ratti printed his "History of Genzano", a village in the district of Rome .
The Ratti family name is recorded in Genoa (in the singular form Ratto) since 1159, and belongs to the Genoa aristocracy. A quarter of Genoa, where the family had its possessions, is still today named Borgoratti or Borgaratti, and a Via Ratti (Ratti Avenue) runs across it.
Coat-of-arms : top, a crowned black eagle on a golden background; bottom, three red balls on a golden background. A variant is illustrated in fig. 7. It is clearly similar to that of the Ratti Opizzone from Tortona and to that of the Ratti from Desio.
Fig. 7. Coat-of-arms of the Ratti family from Genoa (variant).
The Ratti family from Savona. The most famous representative was Giovanni Agostino Ratti, born in Savona (Liguria), 1699, dead in Genoa, 1775, painter and engraver. His works are in several churches of Torino, Savona, Spotorno, Albisola, Pegli, and in the church of Santa Croce in Genoa. His son, Carlo Giuseppe Ratti, born in Savona, 1737, dead in Genoa, 1795, painted in fresco the ceiling of the little hall of the Duke’s Palace in Genoa. Michele Ratti, book-binder, is recorded in Vernazza, 1468 .
The Ratti family from Voghera. Close to Voghera (Pavia, Lombardy) rises Borgoratto Mormorolo, a village named from the Ratti family, once and now flowering in Voghera and in the territory of Pavia.
The Ratti families from Piacenza. First records of the ocurrence of the Ratti family in Piacenza (Emilia) date back to 16th century : Giovanni Giacomo Ratti and Zanino Ratti in 1558, Giovanni Battista Ratti and Lorenzo Ratti in 1576. Two localities of the city remember this name: the slope called ‘Montà di Ratt’ at the end of Via Mazzini, and the church, now destroyed, of San Martino in Borgo also called "San Martino dei Ratti". A noble Ratti family subsisted in Piacenza for two centuries (from 1600 to 1800) and at present days appears to be extinct or migrated. Its origin is uncertain, but it is higly probably connected (as many others with the same name) with the Ratti families of the Ligurian strain, which spread to Tortona, Bobbio, the lower Lombardy and the Emily. The characteristic Ligurian Christian name "Siro", repeated several times in the family, and the centuries-old possessions in Ascona (Santo Stefano d’Aveto), small village in the High Ligurian Appennines (at the border between Piancenza and Bobbio areas) in the Aveto Valley, are rather meaningful. This family branch migrated to Piacenza nearly in 1640; its members were goldsmiths. Coat-of-arms: top, a black eagle in a golden background (as Ratti Opizzone and Ratti from Genoa); bottom, a black rat in a golden background. It is similar to the coat-of-arms of the Rattazzi family from Alessandria (the latter is enriched by a median light-blue strip with three silver stars) .
The Ratti family from Montarsiccio (Bedonia, province of Parma), only ten miles distant from Ascona and Santo Stefano d’Aveto, surely has the same origin as the Piacenza family, and probably is closely related to .
The Ratti "Lizoli" family
Pensa attributed to the Ratti (de’ Lizoli) family from Premana (Lecco, Lombardy) a coat-of-arms quite similar to the Ratti Opizzone one, but he was probably wrong. Actually, there is no sure proof that this Ratti family could be related to the previously mentioned ones, of Piedmontese/Ligurian origin.
This family was mentioned in Premana since the 15th century, as a noble branch - nicknamed Ratti - of the Lizoli (presently Lizzoli) family. The first records concern Zanino nicknamed Ratino (mentioned 1463) and his brother Cristoforo nicknamed Ratto (notary in Premana, 1485), sons of Sir Antonio Lizoli .
For at least one century, family name and nickname were employed either separately or associated: records are given of Giarino, Nicolao and Jacomo Ratto (1558) ; Giovanni Antonio Lizoli or Ratto or Lizoli de Ratti (1610) ; Cristoforo de Ratti or Ratti or Ratto (1610) and Giulio Lizoli Ratto or de Ratti (1602) , both sons of the late Giovanni Antonio Ratti, owners and tenants of iron mines.
Before 1650 the ancient nickname Ratti became definitively a family name in Premana. In the second half of 17th century branches of the family migrated to Venice, firstly as blacksmiths or coppersmiths, then as ironmongers .
Descendants still keep in their family archive a coat-of-arms (fig. 8), very similar to the coat-of-arms of the Liccioli family from Florence (fig. 9), nobles of Fiesole, recorded since 14th century. The tree, illustrated in their coat-of-arms, is probably an olm-oak tree (in Italian: leccio), so the family name Liccioli. It is therefore possible that a branch of the Liccioli family migrated to Premana before 1400, changing then the family name in Lizoli/Lizzoli (following the local dialect).
At present time this Ratti family branch is only represented in Premana, in Venice, and in Montevideo (Uruguay: descendants of Giovanni Domenico Ratti, migrated from Venice in 1870).
Fig. 8-9. Left: coat-of-arms of the Ratti (de Lizzoli) family from Premana. Right: coat-of-arms of the Liccioli family from Florence.
In Venice, anyway, further Ratti families occurr, mostly migrated from Lombardy, but probably original from the Ligurian-Piedmontese strain. The earliest record concerns Paulo de Ratti (recorded in the will - in Latin - of his widow Maria: Venice, August 27, 1391) (fig. 10).
 
Fig. 10. Will of Maria, widow of Paulo de Ratti (Venice, August 27, 1391 A. D.).
Present distribution of the Ratti family name in Italy
This research was carried out looking up the phone books of all Italy (through the web site www.paginebianche.it). Currently more of 3,000 Ratti families are recorded in Italy (fig. 11). Nearly 90% of them are in three regions of northwestern Italy: Lombardy (2,200 families), Piedmont (380) and Liguria (360).
 
Fig. 11. Current distribution of the Ratti families in Italy.
In Como (Lombardy) a branch of the Ratti family devoted itself to silk-spun production since 19th century. Presently, the Ratti society from Cadorago (Como) is a famous industry specialized in production of ties, scarves and foulards: president, Antonio Ratti, vice-president Donatella Ratti. They are also the major shareolders of the society Erre of Como (high fashion accessories), administrated by Erika Ratti. In Rogeno (Como) there also is the registered office of the ISER Enrico Ratti Silk Industry (production and wholesale of fabrics and clothes). A curiosity concerning the Ratti families from Lombardy: Enrico Rinaldo Ratti, son of Anselmo and Francesca Valagussa, born in Cassano d’Adda (Milan) november 30, 1890, signed on the steamer Titanic on 10th april 1912 as restaurant waiter, and died in the ship sinking: it was his first enbark .
Also in Emily-Romagna the family name is well represented (170 families).
In northeastern Italy, on the contrary, the family name is sporadic, with small colonies in Venetia (Venice and Verona). Unknown is the origin of a historic "Fort Ratti" in the Astico Valley close to Arsiero (Vicenza), seat of a military action during the First World War (16th Mmay, 1916) .
In central Italy the Ratti family name is well represented only in Tuscany (280 familes), namely in the Massa-Carrara province, not far from the Ligurian border. This area, famous for marble quarries, was the destination of an important migration of marble miners since 1400-1500. Frrom here many Ratti families migrated to America at the end of 19th century. In Latium nearly 60 families (Rome and Rieti provinces) are recorded today.
In southern Italy, nearly 60 families each in Campania (Naples) and Apulia (Bari, Taranto, Foggia). In the remaining Italian regions the family name is sporadic or absent.
Present distribution of the Ratti family name in Europe and overseas. It occurs also in France (nearly 125 families) and, more sporadically, in Germany, United Kingdom, Spain, Belgium. As said above, the Ratti families from Finland are not original from Italy.
In North America it occurs in Canada (some Rattie, Ratté, Raté families are probably original from France and possibly related to the Ratti families from Nice and Menton) and in the United States. The U.S. Ratti colony is the largest after the Italian one, with residence, for the most part, in the State of New York, but also in Arizona, California, Colorado, Connecticut, Florida, etc. (fig. 12).
Fig. 12. Current distribution of the Ratti families in the United States.
In South America the largest Ratti colony is in Argentina (more than 200 families, mostly in Buenos Aires and Cordoba). Lesser colonies are in Peru, Paraguay, Uruguay.
A small Ratti colony is recorded also in Australia (Melbourne and surroundings: 8 families).
Placenames from the Ratti family name. There are several placenames in Italy - and also in France - surely derived from the Ratti family name.
Liguria: Genoa. Borgoratti (quarter on the hills); Forte Ratti (castle); Via Ratti (avenue).
Piedmont: Alessandria. Borgoratto Alessandrino (village).
Piedmont: Borghetto di Borbara (Alessandria). Castel Ratti or Castel de’ Ratti or Torre Ratti (castle); Cerreto Ratti (wood and village).
Piedmont: Asti. Via Ratti (avenue).
Lombardy: Premana (Lecco). Contrada dei Ratti (quarter).
Lombardy: Piani di Bobbio (Barzio - Lecco). Rifugio Vittorio Ratti (mountain refuge).
Lombardy: Voghera (Pavia). Borgoratto Mormorolo (village).
Venetia: Arsiero (Vicenza). Forte Ratti (fortified battery); Contrada Ratti - Tezze (mountain area).
Emily: Piacenza. Chiesa dei Ratti (church); Montà di Ratt (avenue).
France: Nice. Avenue Ratti; Villa Ratti.
References.
Acerbi E., 1998 - "La cattura di Forte Ratti: bugie e verità". G. Rossato, Novale (Vicenza), 93 pp.
Amati A., 1878 - "Dizionario corografico dell’Italia". Vallardi, Milano, vol. 1-8.
Anonymous, 1987 - "La famiglia Ratti". Il Corno, Premana, a. XXIV, Christmas 1987, pp. 9-12.
Anonymous, 2000 - "I cognomi di Premana: Ratti". Il Corno, Premana, a. XXXVII, n. 1, Easter 2000, pp. 9-11.
Dattero A., 1997 - "La famiglia Manzoni e la Valsassina. Politica, economia e società nello Stato di Milano durante l’Antico Regime". Franco Angeli Storia, Milano, 223 pp..
De Felice E., 1978 - "Dizionario dei cognomi italiani". Mondadori, Milano, 351 pp.
Di Crollalanza G. B., 1965 - "Dizionario storico - blasonico delle famiglie nobili e notabili italiane estinte e fiorenti. Forni, Bologna.
Ferrari L., 1947 - "Onomasticon. Repertorio bibliografico degli scrittori italiani dal 1501 al 1850". Hoepli, Milano, 708 pp.
Gasca Queirazza G., Marcato C., Pellegrini G.B., Petracco Sicardi G., Rossebastiano A., 1990 - "Dizionario di Toponomastica". Utet, Torino, 720 pp.
Gianola C., 1890 - "Notizie storico - statistiche di Premana raccolte ed ordinate dal sacerdote Carlo Gianola parroco di Garbagnate Milanese". Tipografia Salesiana, Torino, 111 pp.
Nappo T., Noto P., 1993 - "Indice biografico italiano". K. G. Saur, München, etc., voll. 1-4.
Nasalli Rocca E., 1936 - "La nobile famiglia Ratti di Piacenza". Rivista Araldica 1936: 147-160.
Orlandi A., 1932 - "Le famiglie della Valsassina". Tip. ed. La Grafica, Lecco.
Pensa P., 1976 - "Le antiche famiglie nobili e notabili del Lario orientale stanziatesi prima del XVI secolo in Lecco - nella Valsassina - nella Valvarrone - nella Val d’Esino e sulla riviera orientale del Lario". Arti Grafiche Colombo, Gessate, 178 pp.
Ratti E., 2001 - "Calderai premanesi a Venezia". A Fööch (Venezia) 11 (3), pp. 2-5.
Spreti V., 1969 - "Enciclopedia storico - nobiliare italiana". Forni, Bologna (reprint of the Milan edition, 1928-1935).
Spreti V., Degli Azzi Vitelleschi G., 1936 - "Saggio di bibliografia araldica italiana". Milano.
Tizzoni M., 1998 - "Il Comprensorio minerario e metallurgico valsassinese". Materiali - Monografie periodiche dei Musei Civici di Lecco, anni IX-X (1994-1995), Lecco, 448 pp.
Zastrow O., 1996 - "La chiesa di san Dionigi a Premana". G. Stefanoni, Lecco, 432 pp.
Venice, January 10, 2002
Additional information follows:
This information has been provided by the author.
I received more information, including the coat-of-arms, concerning the Ratti family from Piuro (Sondrio).   This family gave the name to "Valle dei Ratti" in the territory of the municipality of Verceia (province of Sondrio).
     Marco Ratti, son of Antonio, is mentioned 1426; 20 or 30 years later are mentioned 3 brothers, sons of Giovanni Ratti: sir Giacomo, sir Antonio and sir Gaudenzio. Giacomo had two sons: Gaudenzio (jr.) and Pietro (mentioned 1494); Antonio had a son, Tomaso, husband of Lucia Ravalcada (1506).
     Most of their Christian names (Antonio, Giovanni, Giacomo, Pietro) are the same Christian names as the Ratti from Premana of 15th and 16th century. So, I think that is really possible that the Ratti from Premana (not far from Piuro) are a branch of this family.