In the meantime Niort had been attacked. De Mouy defended the place stoutly, and sallied out and repulsed the enemy. His bravery, however, was fatal to him. A Catholic named Maurevel, tempted by the fifty thousand crowns that had been offered for the assassination of Coligny, had entered the Protestant camp, pretending that he had been badly treated by the Guises. No opportunity for carrying out his design against the Admiral presented itself, and he remained at Niort with De Mouy; who, believing his protestations of attachment for the cause, had treated him with great friendship. As the Huguenots were returning after their successful sortie, he was riding in the rear with De Mouy and, seizing his opportunity, he drew a pistol and shot the Huguenot leader, mortally wounding him. He then galloped off and rejoined the Catholics; and was rewarded, for the treacherous murder, by receiving from the king the order of Saint Michael, and a money reward from the city of Paris.

The garrison of Niort, disheartened at the death of their leader, surrendered shortly after. Several other strong places fell, and all the conquests the Protestants had made were wrested from their hands. The battle of Moncontour was fought on October 3rd. On the 14th the southern troops marched away, and four days later Coligny, with the remains of the army, started from Saintes. He had with him but six thousand men, of whom three thousand were cavalry.

His plan was an extremely bold one. In the first place, he wished to obtain money to pay the German horsemen, by the capture of some of the rich Catholic cities in Guyenne; to form a junction with the army of Montgomery; then to march across to the Rhone, and there to meet the forces of the south, which would by that time be ready to take the field again; then to march north to Lorraine, there to gather in the Germans whom William of Orange would have collected to meet him; and then to march upon Paris, and to end the war by giving battle under its walls.

The Queen of Navarre was to remain in La Rochelle, which city was placed under the command of La Rochefoucault; and the two young princes were to accompany the army, where they were to have small commands. They would thus become inured to the hardships of war, and would win the affection of the soldiers.

Francois de Laville had, with his own troop, ridden off to his chateau from Parthenay on the morning after the battle; Coligny advising him to take his mother, at once, to La Rochelle, as the chateau would speedily be attacked, in revenge for the sharp repulse that the Catholics had suffered there. On his arrival the countess at once summoned all the tenants, and invited those who chose to accompany her; pointing out that the Catholics would speedily ravage the land. Accordingly, the next day all the valuables in the chateau were packed up in carts, and the place entirely abandoned. The whole of the tenants accompanied her, driving their herds before them, as they would find a market for these in the city. As they moved along they were joined by large numbers of other fugitives, as throughout the whole country the Protestants were making for refuge to the city.

When the Admiral marched away, Philip rode with a young French officer, for whom he had a warm friendship, named De Piles. The latter had been appointed governor of Saint Jean d'Angely, which was now the sole bulwark of La Rochelle; and he had specially requested the Admiral to appoint Philip to accompany him. The place was scarcely capable of defence, and the Admiral had only decided to hold it in the hope that the Duc d'Anjou, instead of following him with his whole army, would wait to besiege it.

This decision was, in fact, adopted by the Royalists, after much discussion among the leaders. Several of them wished to press on at once after Coligny, urging that the destruction of the remnant of his army would be a fatal blow to the Huguenot cause. The majority, however, were of opinion that it was of more importance to reduce La Rochelle, the Huguenots' stronghold in the west, and in order to do this Saint Jean d'Angely must first be captured. Their counsel prevailed and, just as the siege of Poitiers had proved fatal to the plans of Coligny, so that of Saint Jean d'Angely went far to neutralize all the advantages gained by the Catholic victory at Moncontour.

Scarcely had De Piles taken the command than the army of the Duc d'Anjou appeared before the walls, and at once opened fire. The garrison was a very small one, but it was aided by the whole of the inhabitants; who were, like those of La Rochelle, zealous Huguenots. Every assault upon the walls was repulsed, and at night the breaches made by the cannon during the day were repaired; the inhabitants, even the women and children, bringing stones to the spot, and the soldiers doing the work of building.

On the 26th of October, after the siege had continued for a fortnight, the king himself joined the Catholic army, and summoned the place to surrender. De Piles replied that, although he recognized the authority of the king, he was unable to obey his orders; as he had been appointed to hold the city by the Prince of Navarre, the royal governor of Guyenne, his feudal superior, and could only surrender it on receiving his orders to do so. The siege, therefore, recommenced.

The walls were so shaken that De Piles himself, after repulsing a furious attack upon them, came to the conclusion that the next assault would probably be successful; and he therefore caused a breach to be made in the wall on the other side of the town, to afford a means of retreat for his troops. His supply of ammunition, too, was almost exhausted.