Complex sentence: The Ketuvim is the last of the three portions of the Tanakh to have been accepted as Biblical canon, it is said that the people of Israel were adding what would become the Ketuvim to their holy literature shortly after the canonization of the prophets.
Split into simpler sentences: The Ketuvim is the last of the three portions of the Tanakh to have been accepted as Biblical canon. Evidence suggests, however, that the people of Israel were adding what would become the Ketuvim to their holy literature shortly after the canonization of the prophets.