The Last Saxon King by Andrew Varga

Sixteen-year-old Dan Renfrew comes from a long line of time jumpers—secret heroes who travel to the past and resolve glitches in the time stream that threaten to alter history. There is just one problem; Dan has never been told any of this. So when Dan accidentally transports himself to England in the year 1066, he becomes trapped in the past. His only hope of returning home is to set history back on its proper course in the Anglo-Saxon age. But Dan finds that fixing history is not that easy—chaos has descended upon England. A Viking horde is ravaging the north while an army of Normans is threatening to invade from the south. And in between them both, desperately struggling to maintain his throne, is the newly-crowned English king, Harold Godwinson. Dan must do everything in his power to return history to its proper path, but he soon discovers an even bigger challenge—a war has broken out in the time jumping community, and a band of malicious time jumpers is threatening the very future of the world.

Young Adult • Historical Fiction/Medieval • Science Fiction/Time Travel