Leonardo da Vinci's surname?

Factual Questions
1

Okay, we all know that Leonardo was his given name, but did he have a surname, one that was used before he became well-known?

All of the sources I find give his father’s name as Ser Piero and his mother’s name as simply Caterina. Leonardo was illegitimate, but “claimed” and provided for by his father. Would he have used his father’s surname? Would he have used his mother’s surname? Is it possible that his mother, being a peasant, didn’t have a surname herself? Is it possible that Leonardo did not have a surname at any point?

2

I belive da Vinci was his surname. Keep in mind that surnames are not always family names, particularly in the past. The use of place of origin (e.g. da Vinci), profession (e.g. Smith), or relationship (MacDonald) was not uncommon. Today, these surnames have transformed into family names.

3

So before he moved to Vinci was he Leonardo de Anchiano? Would his surname change every time he moved, or would it “solidify” when he reached adulthood?

4

Or possibly children did not necessarily have surnames, and he only became “da Anything” when he began his apprenticeship in Florence, at age 14?

5

Well, you only need a surname if people want to distinguish you from someone else with the same name. How big was Anachiano? He could have been “Leonardo, Caterina’s son”, “Leonardo, the bastard”, “Little Leonardo”, etc.

6

Leonardo was born in Vinci, so once he became famouse enough for anyone to care, he was da Vinci from that point on.

7

It appears that his father and grandfather had da Vinci on their names, too; so for all practical purposes, I would say da Vinci was the family name.