Jehoram's brothers -- the other sons of Jehoshaphat -- were Azariah, Jehiel, Zechariah, Azariahu, Michael, and Shephatiah.
Their father had given each of them valuable gifts of silver, gold, and costly items, and also the ownership of some of Judah's fortified cities. However, Jehoram became king because he was the oldest.
But when Jehoram had become solidly established as king, he killed all his brothers and some of the other leaders of Israel.
Jehoram was thirty-two years old when he became king, and he reigned in Jerusalem eight years.
But Jehoram followed the example of the kings of Israel and was as wicked as King Ahab, for he had married one of Ahab's daughters. So Jehoram did what was evil in the LORD's sight.
But the LORD was not willing to destroy David's dynasty, for he had made a covenant with David and promised that his descendants would continue to rule forever.
References for 2 Chronicles 21:7
During Jehoram's reign, the Edomites revolted against Judah and crowned their own king.
So Jehoram went to attack Edom with his full army and all his chariots. The Edomites surrounded him and his charioteers, but he escaped at night under cover of darkness.
Edom has been independent from Judah to this day. The town of Libnah revolted about that same time, because Jehoram had abandoned the LORD, the God of his ancestors.
He had built pagan shrines in the hill country of Judah and had led the people of Jerusalem and Judah to give themselves to pagan gods.
Then Elijah the prophet wrote Jehoram this letter: "This is what the LORD, the God of your ancestor David, says: You have not followed the good example of your father, Jehoshaphat, or your grandfather King Asa of Judah.