Jotham became king after sharing the throne with his father, Uzziah, for eleven years, from 750 to 740 BC. He then ruled alone for five more years, from 740 to 735 BC, totaling sixteen years. Jotham lived at least four more years, as Hoshea rose to power in the northern kingdom in the twentieth year of Jotham son of Uzziah (2 Kings 15:30). However, Jotham's son, Ahaz, had already started ruling alongside him. After Jotham's sixteen official years, Ahaz took over as king (see study note on 2 Kings 16:1–2). Ahaz likely had his official accession ceremony after Jotham's death in 732 BC, so the author of 2 Chronicles counts Ahaz's official reign starting in 731 BC (see 2 Chronicles 28:1).