 In return for the throne, Archduke Ferdinand promised to respect the historic rights, freedoms, laws and customs of the Croats when they united with the Hungarian kingdom and to defend Croatia from Ottoman invasion.The Austrian lands were in miserable economic and financial conditions, thus Ferdinand desperately introduced the so-called Turkish Tax (Türken Steuer).In spite of the huge Austrian sacrifices, he was not able to collect enough money to pay for the expenses of the defence costs of Austrian lands.