This Day in History: February 24

1582 Pope Gregory XIII orders the introduction of the Gregorian calendar

In an effort to bring the calendar back in line with the solar year, Pope Gregory XIII ordered the introduction of a new calendar. The Gregorian calendar, which we still use today, replaced the Julian calendar and made adjustments to the leap year system.

1607 The world's first opera is premiered

Claudio Monteverdi's "L'Orfeo" debuted in Mantua, Italy, marking the birth of opera as an art form. The opera is still performed today and is considered a masterpiece of early Baroque music.

1739 Battle of Karnal: Army of Iranian ruler Nadir Shah defeats the forces of the Mughal emperor of India, Muhammad Shah

The Battle of Karnal was fought between the Persian Empire led by Nadir Shah and the Mughal Empire of India led by Muhammad Shah. The Persian victory marked the decline of the Mughal Empire and the rise of the Persian Empire as a major power in the region.

1821 Agustín de Iturbide and Vicente Guerrero agree to the Plan of Iguala, stating that Mexico will become a constitutional monarchy, Roman Catholicism the official religion and that Peninsulares and Creoles will enjoy equal political and social rights

The Plan of Iguala was a document signed by Mexican revolutionary leader Agustín de Iturbide and insurgent leader Vicente Guerrero. The plan called for the creation of an independent Mexican nation, with a constitutional monarchy as its form of government.

1868 US House of Representatives vote 126 to 47 to impeach President Andrew Johnson

The impeachment of President Andrew Johnson was a significant event in American history. Johnson, who had become president after the assassination of Abraham Lincoln, clashed with Congress over his plans for Reconstruction in the aftermath of the Civil War. The House of Representatives voted to impeach Johnson for violating the Tenure of Office Act, although he was later acquitted in the Senate.

1920 The German nazi party is founded

The Nazi Party was founded in Munich, Germany, by Anton Drexler and Adolf Hitler. The party was initially small and obscure, but would grow in influence in the years leading up to World War II, ultimately leading to the Holocaust and other atrocities committed by the Nazi regime.

1942 The "Battle of Los Angeles" takes place

The "Battle of Los Angeles" was a series of anti-aircraft engagements over the city in response to a rumored but false Japanese attack. The incident caused widespread panic and confusion, but ultimately resulted in no damage or casualties. The cause of the sightings remains a mystery to this day.

1946 General Juan Perón first elected President of Argentina

Juan Perón, a military officer and politician, was elected president of Argentina in 1946. Perón's presidency was marked by a populist agenda, including the creation of labor unions and social welfare programs, but was also criticized for authoritarian tendencies.

2008 Fidel Castro retires as the President of Cuba

After nearly fifty years in power, Fidel Castro resigned as president of Cuba due to health reasons. His brother, Raúl Castro, succeeded him as president,