June 15 has witnessed several notable historical events. In 1215, King John of England signed the Magna Carta, a peace treaty that ultimately failed but inspired democratic principles, including the U.S. Constitution. The first recorded blood transfusion occurred in 1667 by French physician Jean-Baptiste Denys. In 1775, the Continental Congress appointed George Washington as the commander in chief of the Continental Army, a pivotal moment in the American Revolutionary War. Additionally, Delaware's leaders declared independence from Britain in 1776, marking Separation Day. The PS General Slocum disaster in 1904 resulted in over 1,000 deaths, primarily affecting the German American community. In 1944, U.S. Marines assaulted Saipan, a strategic victory in the Pacific during World War II. Other significant events include the release of Marvin Gaye's hit single in 1973, the debut of Nirvana's album in 1989, and the passing of jazz legend Ella Fitzgerald in 1996.