Complex sentence: In 716, Chilperic II the king of the Franks and Ragenfrid the mayor of the palace led an army into Austrasia, near Cologne where Plectrude had shut herself up.
Split into simpler sentences: In 716, Chilperic II the king of the Franks and Ragenfrid the mayor of the palace. Together they led an army into Austrasia, near Cologne where Plectrude had shut herself up.