He came back from a trip down there one time and was upset because he said Uncle Fabrice treated him like a dunce in front of customers.
He was sent to various schools, but was generally regarded as a dunce, and when he was sixteen years of age he entered his father's foundry, working for seven years with no wages beyond a little pocket money.
His father was called Bonaccio, most probably a nickname with the ironical meaning of "a good, stupid fellow," while to Leonardo himself another nickname, Bigollone (dunce, blockhead), seems to have been given.
And the woman who wrote this, whoever she is, isn't any dunce.
He passed from the school at Kilkenny to Trinity College, Dublin (1700), where, owing to the peculiar subtlety of his mind and his determination to accept no doctrine on the evidence of authority or convention, he left the beaten track of study and was regarded by some as a dunce, by others as a genius.