At the beginning of June 1664 a large Ottoman army, numbering up to 100,000 men (some sources mention even much more), including around 40,000 Ottoman and 30,000
Tatar fighters, led personally by the Grand Vizier Köprülü, was moving from
Constantinople to the northwest and approaching Novi Zrin (later to fight in the
Battle of Saint Gotthard on 1 August 1664). The defenders of Novi Zrin consisted mostly of Croatian and German soldiers (around 3,000 men in total), while the majority of the Habsburg army (30,000 men) under command of
Raimondo Montecuccoli, encamped not far from the battle field, awaited the outcome of the battle. On 5 June 1664 Köprülü ordered
siege and continuous attacks upon the castle. After a few weeks of fighting, with exhausted defenders receiving only insignificant reinforcements from the Emperor's headquarters, the Turks managed to dig
lagums, or tunnels, below the
bastions and ignited
gunpowder to blow them up. On 7 July 1664 the strong explosions destroyed parts of the walls, making big holes. Aggressors consequently rushed and penetrated into the castle. As the siege of Novi Zrin was ongoing, Crimean Tatars led by kahn's son Ahmed Giray raided the Croatian countryside, which according to
Evliya Celeby's Seyahatnâme resulted in sack of
Krapina. The surviving and enormously outnumbered Croatian defenders were forced to withdraw from the castle and abandon the Mura River area. Ottoman commanders gave the order to their soldiers to destroy Novi Zrin completely to the ground and then marched their army northwards, first towards
Kanije and then towards Saint Gotthard. == Aftermath ==