Recorded in a number of forms which include: Diego, Diago, Dieguez, Diez, and Diaz, (Spanish) and Diogo and Dias (Portugese), this is a surname of the Iberian Peninsula. However spelt it is however almost certainly of Roman (Latin) origins, dating back to the time when the Roman Empire, in probably the first known attempt to create a united continent, occupied the whole of Europe in the period before the 5th century a.d. The early spelling forms were probably 'Didagus or Didacus' which it is believed, originated themselves from an even early Greek word 'didakhe' meaning 'doctrine'. Other recent suggestions are that this surname derives from city name of Santiago, whilst another suggestion is that it is a form of Jacobus or Jacomus, the modern Jacob and James. With both these 'suggestions' the etymology used is at best convoluted. What is certain is that after the Romans retreated the Pensinsula was occupied for some three hundred years by the Huns and the Goths. These tribes swept down from Germany, and they left as their permanent reminder many of Spain and Portugal's most famous surnames including Gonzales and Carlos. The modern forms of the surname derive from after this period, although the actual surnames themselves were not recorded until after the 14th century.