of the United States Aaron Burr for treason. May 24 – Siege of Danzig ends after 6 weeks with Prussian and Russian defenders capitulating to French forces. May 29 – Selim III, Ottoman Emperor since 1789, is deposed in favour of his nephew Mustafa IV. May 31 – Primitive Methodism originates in an All Day of Prayer at Mow Cop, in the north midlands of England. June 9 – The Duke of Portland wins the United Kingdom general election. June 14 – Battle of Friedland: Napoleon decisively defeats Bennigsen's Russian army. June 22 – Chesapeake–Leopard affair: British Royal Navy warship HMS Leopard attacks and boards United States Navy frigate USS Chesapeake off Norfolk, Virginia, seeking deserters. This act of British aggression played a role in the run-up to the War of 1812. July–September July 5 – A disastrous British attack is mounted against Buenos Aires, during the second failed invasion of the Río de la Plata. July 7–9 – The Treaties of Tilsit are signed between France, Prussia and Russia. Napoleon and Russian Emperor Alexander I ally together against the British. The Prussians are forced to cede more than half their territory, which is formed into the Duchy of Warsaw in their former Polish lands, and the Kingdom of Westphalia in western Germany. The Free City of Danzig is also formed (established September 9 by Napoleon). July 13 – With the death of Henry Benedict Stuart, the last Stuart claimant to the throne of the United Kingdom, Jacobitism comes to an effective end. July 20 – Nicéphore Niépce is awarded a patent by Napoleon Bonaparte for the Pyréolophore, the world's first internal combustion engine, after it successfully powers a boat upstream on the river Saône in France. August 17 – The North River Steamboat, Robert Fulton's first American steamboat, leaves New York City for Albany on the Hudson River, inaugurating the first commercial steamboat service in the world. September 1 – Former U.S. Vice President Aaron Burr is acquitted of treason. He had been accused of plotting to annex parts of Louisiana and Mexico, to become part of an independent republic. September 2–7 – Battle of Copenhagen: The British Royal Navy bombards Copenhagen with fire bombs and phosphorus rockets, to prevent the Dano-Norwegian navy from surrendering to Napoleon; 30% of the city is destroyed, and 2,000 citizens are killed. September 7 – Robert Morrison, the first Protestant missionary to China,