Complex sentence: He made a treaty whit the Frankish mayor of the palace Ragenfrid, his armies could in 716 enter the Frankish land till Cologne, where they where victorious in the Battle of Cologne.
Split into simpler sentences: He made a treaty with the Frankish mayor of the palace Ragenfrid. In 716 his armies could enter the Frankish land as far as Cologne, where they where victorious in the Battle of Cologne.