דברי הימים ב, פרק ל״ג, פסוק א׳

A boy taking the throne marks the beginning of a distinct and lengthy era for the kingdom in Jerusalem. Manasseh assumes leadership while still a child, stepping into power at just twelve years old. Despite his youth at the start of his rule, he goes on to lead the nation for an unprecedented amount of time. His reign lasts for fifty-five years, making it the longest rule of any king in the history of Israel [ביאור שטיינזלץ].

The historical record of this royal transition, along with the events that immediately follow, is drawn directly from the Book of Kings, which contains the parallel account of his early days in power [מלבי״ם].