 Complete the following phrase:  The rivalry is largely held to have begun when upon the death of the Habsburg Emperor Charles VI in 1740, King Frederick the Great of Prussia launched an invasion of Austrian-controlled Silesia, starting the First Silesian War of three Silesian Wars to come against Maria Theresa. Frederick had broken his promise to acknowledge the Pragmatic Sanction of 1713 and the indivisibility of the Habsburg territories, whereby he sparked off the panEuropean War of the Austrian Succession. He decisively defeated the Austrian troops at the 1742 