Siege of Cēsis Castle (1577)

The siege of Cēsis Castle in 1577 was a part of Ivan the Terrible's campaign to conquer Old Livonia.
Explosion.
Cēsis Castle was guarded by the Polish troops being one of region's most important fortresses. 
Based on , the castle had only a few hundred people. Most of them were women and children while the Muscovites had thousands of men, with the heaviest of weapons. Having knowledge of the Muscovite ruler's brutality to his prisoner, townsmen of Cēsis sought shelter and refuge inside the castle.
After the five-days-long shelling cracks and holes caused by the heavy artillery of the Muscovites, the castle was extremely damaged and the  cesis castle was in serious danger along with the people in it. The townsmen of Cēsis however decide not to give themself up but rather decided to blow themselves up with gunpowder.
Literature.
 Salomon Henning's "Chronicle of Livonia and Courland" gives the most touching description of the mass suicide:One should have seen this sorrow beyond all sorrow as the good people knelt in the room beneath which the gunpowder had been placed. Man and wife held each others' hands, children gathered around their parents, some still nursing at their mothers' breasts, all awaiting blessed St. Simeon's hour. Nor, as the Muscovite soon hereafter began to storm and invade the castle, was it long delayed. The gunpowder was ignited and all were blown up, aside from those who had hidden elsewhere in the castle...