Complex sentence: A formula for the Jewish oath was fixed by Charlemagne, and Jews were allowed to enter into lawsuits with Christians, and in their relations with the latter were restrained only from making them work on Sunday.
Split into simpler sentences: A formula for the Jewish oath was fixed by Charlemagne. They were allowed to enter into lawsuits with Christians, and in their relations with the latter were restrained only from making them work on Sunday.