Any document that was written during the event by someone who witnessed the event, such as a document on the Battle of Gettysburg, a primary source document would be by someone who was at the battle, and could see what was happening first hand.
The reasons are that Rehoboam attempted to continue his father, Solomon's unwise policy of swinging taxes and then arrogantly increased them when the Israelites complained. In a very short time, the Israelites rebelled and split from Israel, forming their own kingdom called Israel.
He was white and Rudyard was mad because the man was white
It helped with the expansion of the spanish empire with the colonisation of north/south america (Bonus fact: they caused mexico with their constant raiding of gold and adultery upon the tribes)