Input (grade 13): When a commune was formed, all participating members gathered and swore an oath in a public ceremony, promising to defend each other in times of trouble, and to maintain the peace within the city proper.
Output (grade 8): When a commune was formed, all particpitating members gathered and swore an oath together, in public, they would defend each other in time of trouble. In addition they would swear to maintain the peace within the city proper.