The Treaty of Alcañices is signed between the Kingdom of León and the Kingdom of Portugal, resolving territorial disputes and establishing the border between the two kingdoms, one of the oldest and most stable borders in Europe, often referred to as La Raya or A Raia. The agreement also fostered an alliance between Portugal and Castile.
View Historical Events by Day:
What Happened Today in History on September 12
Explore the historical events that shaped our world on September 12th. From major milestones to cultural achievements, see what happened on this day in history. Dates for earlier events may be approximate.
Note: Sources for the historical content shown, include research and reviews of relevant Online History Resources or printed material. When possible, we show a link to a source which provides additional or unique perspective about the event.
We do our best to provide accurate information but would appreciate being notified if any incorrect information is found. You may do so by using our Feedback link.
English explorer Henry Hudson discovers Manhattan Island and sails up the river that would later bear his name. More
The Treaty of Sztumska Wieś is signed, ending the Polish-Swedish War and recognizing Sweden's control over Livonia.
The Battle of Vienna occurs, as an alliance of European powers successfully repels the Ottoman Empire's siege of the city. The decisive European victory halted Ottoman expansion into Central Europe and led to a major shift in the balance of power in favor of the European powers.
The Battle of Vienna takes place, with the Holy League forces defeating the Ottoman Empire and ending their siege of Vienna.
The Battle of Rio de Janeiro starts. It was a raid in September 12–22, 1711 on the port of Rio de Janeiro during the War of Spanish Succession by a French squadron under René Duguay-Trouin.
The Portuguese defenders, including the city's governor and an admiral of the fleet anchored there, were unable to put up effective resistance in spite of numerical advantages and the city had to pay a ransom to avoid destruction of its defenses.
Lascaux cave paintings of animals are accidentally discovered by four boys examining a fox hole down which their dog had fallen on the hill of Lascaux, France.
The boys, in awe of what they had found, told their teacher, after which the process towards excavating the cave was set in motion. By 1948 the cave was ready to be opened to the public.Lascaux is located in the Dordogne region of southwestern France, near the town of Montignac. It is a cave complex renowned for its Palaeolithic art, featuring well-preserved paintings of animals that are estimated to be up to 20,000 years old. The original cave is now closed to the public for preservation, but you can visit replicas like Lascaux IV to experience the art. More
.jpg?auto=format,compress&fit=clip&max-w=1600)
The RMS Laconia was sunk by the U-156 German Submarine. The ship was carrying 268 British soldiers and 80 civilians, and 1,800 Italian prisoners of war who were being guarded by 160 Polish soldiers. Some 1,500 of Laconia’s passengers survived. primarily due to the efforts of the U-156 and three other German submarines which participated in the initial rescue operations. More
A military coup takes effect effect in Turkey headed by General Kenan Evren. The event and following actions created a climate of fear in Turkey with widespread repression, mass arrests of over 600,000 people, torture, and executions.
The Turkish Armed Forces ruled the country before democracy was restored with the 1983 Turkish general election. This period saw an intensification of the Turkish nationalism of the state, including banning the Kurdish language. Turkey partially returned to democracy in 1983 and fully in 1989.