Rapid development began in 1547 under the ruling Zrinski family. In 1579 the craftsmen and merchants outside the walls of Čakovec Castle (csáktornyai kastély) were granted the right to trade; this was the beginning of the formal and legal city structure. The area was of importance as a trade center with Habsburg Kingdom of Croatia and Habsburg Kingdom of Hungary positioned nearby on the main roads, facilitating the exchange of goods, crafts and ideas. The region was also a military buffer zone against the expanding Ottoman Empire.