Albert Barnes Commentary 2 Chronicles 33:1

"Manasseh was twelve years old when he began to reign; and he reigned fifty and five years in Jerusalem." — 2 Chronicles 33:1 (ASV)

Compare the references and notes. The author of Chronicles differs from Kings primarily in its additions (see the note on 2 Kings 21:17). The central part of this chapter (2 Chronicles 33:11–19) is almost entirely new material.