Immediately upon his accession, Stephen set out to resolve all disagreements within the royal family in order to strengthen his own position. His relations with his stepmother, the 37-year-old Queen Catherine, had been strained during his father's lifetime, but he now guaranteed that she would retain her title and privileges. Her father, Stjepan Vukčić Kosača, wrote to Venetian officials that the King had "taken her as his mother", Vojača having already died by the time he ascended the throne. Kosača was the kingdom's most powerful nobleman, and had been engaged in a never-ending conflict with Stephen's father. It appears that he nevertheless refrained from claiming the Bosnian crown for his adolescent grandson Sigismund, Catherine's son and Stephen's half-brother, probably realizing that Bosnia needed a strong, mature monarch in the time of peril. Stephen Tomašević took the Venetians' advice to make peace with his stepgrandfather, thus finally ensuring the nobility's absolute support of their king. He then focused on improving Bosnia's economy, which became stronger than ever during his reign, and ensuring that the state would collect more profit from the flourishing metalworking trade.