Is it possible to read the history of King Arthur?

It's possible, but not easy unless you find a modern translation. Look in your library for Morte d'Arthur. It's usually in two volumes written in Early or Middle English. Of course, it's not really History since King Arthur is considered a Legend and there is no concrete evidence that such a person existed. Another useful story of Arthur is found in Geoffrey of Monmouth's Historia Regum Britannae, which has been translated into English several times. Remember that medieval accounts were often not consistent with one another, and almost any major point that one author makes will be implicitly or explicitly denied by another.