Germany and its allies invaded the Kingdom of Yugoslavia on 6 April 1941, shortly after the Cvetković–Maček Agreement that created an autonomous Banovina of Croatia was signed in August 1939. The agreement had caused resentment and opposition among the Serbs. On 10 April 1941, the Independent State of Croatia (NDH) was proclaimed and was initially met with enthusiasm. Vladko Maček, the leader of a powerful Croatian Peasant Party (HSS) and the "de facto" political leader of Croats at the time, refused Germans′ offers to head or take part in the government of the NDH and following the invasion opted for political passivity. Under the rule of the Ustashe party that took power, the NDH's constitution was based on a totalitarian ideology that developed under the influence of Nazism and Fascism. Racial laws were soon enacted and the Ustaše targeted Serbs, Roma and Jews for extermination. Anti-fascist Croats were also persecuted by the regime. Dissatisfaction of the Croatian people with Ustaše rule started almost immediately with the beginning of these persecutions.