Sponza families are often Italians and they are mostly from Rovinj , less frequently Croats (from Pula ). In the past century, relatively most of Croatian residents bearing this family name were born in Pula and Rovinj.
Prevalence
About 90 people with faimily name Sponza live in Croatia today, in 30 households. There were 510 of them in the middle of the past century, and their number decreased significantly. They are located in threee Croatian counties, four cities and threee other places, mostly in Rovinj (65), Pula (20), Rovinjsko Selo (<5), Zagreb (<5), and in Nova Mokosica (<5).
Outside Croatia
At least three families with this surname emigrated from Croatia to: Australia (1), the United States (1), and to Sweden (1). Family name Sponza is present in 17 countries worldwide.
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 2007 in source Encyclopaedia of Croatian Surnames.