Complex sentence: First inclined to leniency, the king freed them and ordered them to return to their homes, but, on March 17,200 men tried to storm one of the city entrences at the foot of the castle.
Split into simpler sentences: First inclined to leniency, the king freed them and ordered them to return to their homes. But on March 17,200 men tried to storm one of the city entries, at the feet of the castle.