Israel Kings: Same Name, Same Time
Israel Had Two Kings with the Same Name at the Same Time... Twice!
While Israel was divided into two kingdoms, there were two times in their history that each kingdom had kings with the same name!
From about 852 BC to 841 BC, there was a King Jehoram of Judah and a King Jehoram of Israel (Divided).
Then, from about 798 BC to 796 BC, there was a King Jehoash of Judah and a King Jehoash of Israel (Divided).*
Both sets of kings had alternate spellings that were also shared. Jehoram can be Joram and Jehoash can be Joash; so that doesn't exactly help clear things up!
Worthy of note is that there was also a King Jehoahaz of Judah and a King Jehoahaz of Israel (Divided), although they didn't rule at the same time. It can also be said that there were actually three kings who's names were Jehoahaz since that was an alternate name for Ahaziah, King of Judah!
It is confusing, however, there's a shared, similar meaning between all of these names which was likely the cause of their popularity. Jehoahaz and Ahazriah mean The Lord Holds/Possesses, Jehoash means The Lord Has Given and Jehoram means The Lord Exalts. Basically, their names claim the authority of the Lord as rulers. Add in the fact that the Jews were accustomed to rulers passing on their names, like the Pharaohs of Egypt, it's not too surprising that they might also try to assert authority over the other by having these types of monikers (names).
*Note: The tidbit about the two kings named Jehoash/Joash ruling at the same time comes from historical sources outside the Bible. The Bible only briefly mentions Joash, King of Israel.