From the original quests to Croatia to the different rulers, all of these events have an effect on the colonization of Croatia. The Battle of Mohacs was very important in 1526, because it resulted in Croatia falling under Turkish Rule. June 25, 1991 was also an important day in Croatia History. Croatia declared independence from Yugoslavia on this day, making it the country's statehood day. In 2013, Croatia made a huge step by joining the European Union.