Bernard I was the illegitimate son of Pepin I and an unknown mother. The details of his life before becoming king are shrouded in obscurity. What is known is that he stayed in Italy with his father until Charlemagne's death in 814. He is said to have participated in several battles in the Unification Wars under the command of his father in order to learn effective fighting and leadership styles. Most of his time, however, was spent in Italy, learning how to lead a nation.