Complex sentence: In 1570, Baron George Khevenhüller acquired the citadel by purchase, fortifying it against the Turkish invasions, building an armoury and 14 gates from 1570-1586.
Split into simpler sentences: In 1570, Baron George Khevenhüller acquired the citadel by purchase. He fortified it against the Turkish invasions of the region, building an armory and 14 gates from 1570-1586.