|Region of origin||medieval Spain|
|Related names||Diogo, Tiago, Santiago; Jacob/James, Jacobo|
|Look up Diego in Wiktionary, the free dictionary.|
Diego is a masculine given name. It is believed to derive from the Greek διδαχη (didache), "teaching", then translated into the Latin word "Didacus" (in Modern English learned, cultured). Etymological evolution of the name shows that it may be eventually be originated from "Iakobos", then evolved into the spanish "Yago" then Santiago ("Santiago"), and finally re-analysed as San Diego.
Nowadays, the name Diego is popular in Spanish-speaking countries (Spain, Uruguay, Chile, Mexico) as well as in Italy. Diego, Santiago and Sandiego are sometimes found as surnames. The forms Tiago, Thiago, Diago and Diogo are seen mostly in Portuguese speaking (lusophone) countries.
During the medieval era, the names "Sant Yago", "Diago" and "Diego" seem to have coexisted. "Sant Yago" is used, for example, in a letter by James II of Aragon dated 1300: "[...] maestro de la cavalleria de Sant Yago et de la dita orden [...]".
"Diago" is recorded, for example, in "Et fue a casa del Rey. e mostrolo a don diago que era adelantado del Rey" (Fuero de Burgos, c. 1240)
"Diego" as a generic name or term for a Spaniard is documented from around 1615, and "dago" is used as such still in the 19th century. By the early 20th century, the term "dago" became an ethnic slur chiefly for Italian Americans, besides also for anyone of Hispanic or Portuguese descent.
The patronymic for Diego is Díaz in Castillian (used for example by Rodrigo Díaz de Vivar, better known as El Cid) and Dias in Portuguese. Like many patronymics, these have become common surnames in Spanish- and Portuguese-speaking regions. The form Diéguez is much less common; Diegues can be found in Portuguese-speaking countries. de Diego and Diego can also be found as surnames.
- González, Félix Rodríguez (1996). Spanish Loanwords in the English Language: A Tendency Towards Hegemony Reversal. Walter de Gruyter. p. 115. ISBN 9783110148459. Retrieved 15 February 2013.