1265 First English Parliament is summoned without royal command, in this instance by Simon de Montfort, Earl of Leicester. It meets in Westminster Hall.

1841 China cedes Hong Kong Island to Britain during the First Opium War

1921 Republic of Turkey is declared from the remnants of the Ottoman Empire

1942 Nazi officials hold the notorious Wannsee Conference in Berlin to coordinate the “Final Solution”, the extermination of Europe’s Jews

1945 Franklin D. Roosevelt is sworn in for an unprecedented and never-to-be-repeated fourth term as US President

1981 Ronald Reagan is inaugurated as the 40th President of the United States

2009: Barack Obama is inaugurated as the 44th president of the United States, becoming the first African American to hold the office. Joe Biden becomes the 47th Vice President.

2025: Chinese startup DeepSeek launches the AI model R1, with capabilities similar to other AI models but at a fraction of the cost, prompting experts to call it a “Sputnik moment”

Source: Onthisday.com