The event of Leonardo da Vinci's birth was recorded by his grandfather, Antonio, then about eighty years old, on the back page of an old notebook that had once belonged to his grandfather. On it he had already noted the births and baptisms of his own four children. There was just room at the bottom of the page to record this new arrival, this new generation -
- There was born to me a grandson, the son of Ser Piero my son, on the 15th day of April, a Saturday, at the 3rd hour of the night. He bears the name Lionardo.
The clock was then reckoned from sunset (or more precisely from the ringing of the Ave Maria bell after vespers). The third hour of the night was about 10:30 p.m.