Prussian claims on possessions of Austrian Habsburgs served the casus belli of the war for Austrian succession. There possessions were gained after the death of emperor Charles IV by his daughter Maria Theresa due to the absence of direct male heirs. Prussian king refused to recognize the rights of Maria Theresa and in 1740 captured Silesia, an Austrian province. Prussian king Frederick II gained support of Bavaria and France. England participated on the side of Austria. After concluding in 1746 the agreement between Austria and Russia, positions of the anti-Prussian coalition were much enforced to speed up the end of the war. Maria Theresa preserved the empire crown, though Silesia remained in hands of Frederick.