1800 followed by 1801
July–September
July 2 – The Union with Ireland Act 1800 is passed by the Parliament of Great Britain; the Irish Parliament passes similar legislation in the following month, uniting the two kingdoms and abolishing the Parliament of Ireland.
July 10 – Fort William College is established by Lord Wellesley, British Governor-General of India, in Calcutta, to promote Bengali, Hindi and other vernaculars of the Indian subcontinent.
August 1 – King George III gives royal assent to the second Act of Union to unite the Kingdom of Great Britain and Kingdom of Ireland (both ruled by him) into the United Kingdom of Great Britain and Ireland, effective on January 1, 1801.
August 30 – The plot by African-American blacksmith and slave Gabriel Prosser to seize Richmond, Virginia, and guide a slave uprising, is thwarted by a massive downpour on the evening that it is set to begin; two other slaves have revealed Prosser's plans to authorities, who have prepared to follow him to the rendezvous point and arrest the conspirators, so that "neither the geographical extent of the plot nor the number of insurgents in the conspiracy was revealed"; eventually, 25 slaves, including Prosser, will be captured, tried and hanged.
September 4 – Siege of Malta (1798–1800): The French garrison in Valletta surrenders to British troops, who had been called at the invitation of the Maltese. The islands of Malta and Gozo become the Malta Protectorate.
September 30 – The Convention of 1800, or Treaty of Mortefontaine, is signed between France and the United States of America, ending the Quasi-War.