Complex sentence: Almost immediately in the aftermath of the war informal patrols sprang into action; later city and rural police squads, along with the help of Union army officers, patrolling practices were revived among free men.
Split into simpler sentences: Almost immediately in the aftermath of the war, informal patrols sprang into action. Later, city and rural police squads, along with the help of Union army officers, revived patrolling practices among free men.