Balian Zosimus was born in 167 AYZ in Tyr. He was the second child of his mother, who had a daughter, Melanie, from a previous marriage, and the second child of his father, who also had a daughter, Laura, from a previous marriage.
He grew up on the family estate, Isidore, alongside his half-sisters Melanie and Laura and his father's ward, Vincent. The four children were very close when they were young, vowing to always look out for each other.
Despite the infamy surrounding the Vormundist religion, Gavin raised his children in the faith.
During the War of Succession, Gavin sided with Prince Claudius. He was eventually killed in battle. As punishment for betraying the crown, King Aldous took the Zosimus family hostage and burned Isidore to the ground. All of the children attempted to flee, but only Vincent escaped.
The family was quickly separated from one another. Balian was taken from his mother and sent to a boys' camp along with other sons of traitorous lords. There, his face was mutilated and he was forced to train to become a warrior.
Four years later, having excelled in his combat training, Balian was permitted to become a knight. Waiting in line to be knighted by the queen, he was stunned to realize the queen was none other than Laura. The two were reunited, and Laura made him her personal bodyguard.