The Ottoman military's regularized use of firearms proceeded ahead of the pace of their European counterparts. The Janissaries had been an infantry bodyguard using bows and arrows. During the rule of Sultan Mehmed II they were drilled with firearms and became "perhaps the first standing infantry force equipped with firearms in the world." The Janissaries are thus considered the first modern standing armies. The combination of artillery and Janissary firepower proved decisive at Varna in 1444 against a force of Crusaders, Başkent in 1473 against the Aq Qoyunlu, and Mohács in 1526 against Hungary. But the battle which convinced the Safavids and the Mughals of the efficacy of gunpowder was Chaldiran.