North of Eger lay the poorly reinforced city of Kassa (present-day Košice), the center of an important region of mines and associated mints, which provided the Hungarian kingdom with large amounts of quality silver and gold coinage.The fortress of Eger was built on the ruins of an earlier stone fort, which replaced an ancient earthen encampment, possibly erected by the Huns.Among the approximately 1,530 combat-ready personnel there were only a handful of foreign mercenaries: Dobó had hired six cannonmasters from Germany in order to make the most efficient use of Eger's artillery.During the siege, Bornemissza devised primitive but lethal grenades and powderkeg-sized bombs to use against the attackers as well as a water-mill wheel packed with gunpowder which he rolled into the Ottoman ranks.Even after the storage tower containing 24 metric tons of black gunpowder exploded and caused extensive structural damage, the invaders still could not find a way into the castle compound.Ahmed was the senior and contributed twice as many troops to the united army, but Ali showed more strategic talent and proved his skill in artillery, badly damaging the castle walls with his battery of just four large siege guns.During the siege, the Ottoman army ran out of gunpowder and cannonballs (which were carved out of marble) at least twice, limiting Ahmed's use of heavy artillery for a week or more.It chronicles the events leading up to and including the siege and tells the tale of Gergely Bornemissza, as well as Captain Dobó, and his co-commander István Mekcsey.Bertalan Székely's painting Az Egri Nők (Women of Eger) depicts the defense of the fortress, especially by the womenfolk, and hangs in the Hungarian National Gallery in Budapest.