On this day in 1788, the Habsburg Empire, more commonly referred to as the Austrian Empire and later the Austro-Hungarian Empire, joined the Russo-Turkish War a year after it began. The war began when Catherine the Great of Russia marched into Crimea and violated terms of the treaty that ended the previous war between the two powers. The Ottomans promptly declared war, but they were not prepared for the joint powers of two of the most powerful nations in Europe and suffered many losses. These losses affected the Turkish Sultan so much that he died. The war ended with Turkish Sultan Abdul Hamid I surrendering to Russia, where he gave them Crimea and other small territories on their border, which stayed largely unchanged. Although Prussia was had signed an offensive pact with the Ottomans, it instead pressured Sweden to attack Russia, despite it being ill-prepared to do so. Russia in turn persuaded Denmark-Norway to declare war on Sweden. The war ended in 1792.