What were the major events in the life of Frederick Douglass that formed his identity?

The first major life event that formed Frederick Douglass's identity was his witnessing his Aunt Hester being brutally whipped. This event occurred when Douglass was very young. At the time he did not understand why his aunt was being beaten. However, the event frightened him and taught him that the world was fundamentally unsafe for him and those he loved.
A second event in early childhood that shaped Douglass's identity was his being sold away at the age of seven from his plantation of birth. Douglass was taken from his friends and family and placed in an unfamiliar and decidedly more brutal environment. Douglass would later note that this was when he began to understand what slavery was. He began to understand how the system of American slavery worked to dehumanize both enslaved people as well as those who held them captive.
A final defining moment in Douglass's early childhood was his learning to read. Upon learning to read, Douglass began to realize that the oppression of black people is a matter of social hierarchy and racial brutality. The oppression of black people was not due to innate inferiority (as he had previously believed). Learning to read marked a turning point when Douglass began to believe that he could eventually achieve emancipation and help abolish the system of slavery itself.