He was called "The Peaceful," because in contrast to David, his father, he secured victories by treaties and accommodation rather than by war; and Jedidiah (Beloved of Yahweh), because of the wisdom and goodness characteristic of his earlier years.
The sources for his life are: III Kings, 1-12; II Par 1-9.
Although not the logical heir, being the second son by Bethsabee (Bathsheba), he was the favorite, and was chosen to succeed his father.
Coming to the throne at the age of eighteen, he ruled for forty years.
Unsurpassed among the Hebrews for sagacity, peace enabled him to organize the kingdom; provide for its defense by means of fortresses and a standing army; advance the orderly administration of justice; develop trade; and embellish the capital with magnificent edifices, the most noteworthy being the temple and his own palace.
The expenses for these, however, as well as for his harem in later years, became so burdensome that on his death the kingdom was rent asunder.
Many scholars think that the number of his wives and concubines should be set at 70 and 300, respectively, and that the last number may have represented female slaves in attendance upon the women.
His voluptuousness and his efforts to please foreign consorts brought him so low that he practised idolatry.
Some think that he received the grace of final repentance.
New Catholic Dictionary