Mozart's first composed piece

At the age of five, he was already composing little pieces, which he played to his father who wrote them down, these early pieces, K. 1–5, were recorded in the Nannerl Notenbuch. There is some scholarly debate about whether Mozart was four or five years old when he created his first musical compositions, though there is little doubt that Mozart composed his first three pieces of music within a few weeks of each other: K. 1a, 1b, and 1c.