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On This Day in History: July 15

Explore the historical events that shaped our world on July 15th. From major milestones to cultural achievements, see what happened on this day in history. Dates for earlier events may be approximate.

388 CE, July 15

The Eastern Roman Emperor Theodosius I defeats the Western Roman usurper Magnus Maximus at the Battle of the Save (also known as the Battle of Poetovio) circa July 15, 388 AD, leading to Maximus's capture and execution in Aquileia, leading to Theodosius's securing control over the unified Roman Empire.

Theodosius I KUDOS 365 BIOGRAPHY SERIES

Theodosius I, also known as Theodosius the Great, was a Roman emperor whose reign marked one of the decisive turning points in late imperial history. Born in Hispania in 347, he came from a military family and rose through the Roman army during a period of crisis along the empire’s frontiers.

In 379, after the eastern emperor Valens was killed by Gothic forces at the Battle of Adrianople, Theodosius was appointed emperor in the eastern half of the Roman Empire. He inherited a weakened army, unstable frontier conditions, and the difficult task of restoring imperial authority. His settlement with the Goths in 382 allowed them to live inside imperial territory as allied peoples, a practical but controversial arrangement that reflected the empire’s changing military realities.

Theodosius is especially remembered for his role in the Christianization of the Roman state. In 380, he issued the Edict of Thessalonica with his co-emperors, making Nicene Christianity the officially favored form of Christianity within the empire. His later policies restricted traditional pagan worship and strengthened the institutional position of the Christian church.

His reign also included conflict and moral controversy. In 390, after a massacre at Thessalonica carried out by imperial troops, Bishop Ambrose of Milan compelled Theodosius to perform public penance. The episode became an important symbol of the growing moral authority of Christian bishops in imperial politics.

Theodosius defeated rivals in civil wars and, for a brief period, ruled both eastern and western parts of the Roman Empire. After his death in Milan in 395, the empire was divided between his sons Arcadius in the East and Honorius in the West. Later historians often regard him as the last emperor to rule a united Roman Empire.

Theodosius’s legacy is complex. He defended imperial unity and strengthened Christianity’s public role, but his reign also revealed the empire’s dependence on negotiated military settlements and its movement toward permanent eastern and western courts. His life stands at the boundary between the classical Roman world and the Christian late antique empire.

1099 CE, July 15

The Crusaders, led by Godfrey of Bouillon, capture the city of Jerusalem from the Fatimid Caliphate, marking the conclusion of the First Crusade.

1101, c. July 15

Following William Rufus's death, Robert Curthose, Duke of Normandy attempted to take the English throne from his youngest brother, Henry I, landing at Portsmouth in c. July,1101, but failing to secure the crown and signed the Treaty of Alton surrendering his claim and agreeing that if either brother died without an heir, the other would inherit the land. He was ultimately defeated by his brothers' Henry military and political maneuvers.

1310 CE, July 15

The Council of Ten is established in Venice on July 15, 1310, with temporary emergency powers to suppress the rebellion led by Bajamonte Tiepolo and restore order. After the revolt was crushed, the council's authority was continuously renewed, and in 1335 it was made a permanent body. The council remained a powerful, secretive and influential governing body until the fall of the Republic of Venice in 1797. More

1427 CE, July 15

The Siege of Montargis in France begins during the Lancastrian phase of the Hundred Years' War. It took place from July 15 to September 5, 1427, and it resulted in a decisive French victory.

1486 CE, July 15

The printing of the first edition of "Malleus Maleficarum," a treatise on witchcraft, is completed around July 15, 1847, in Germany, contributing to the witch-hunt hysteria of the time.

July 1-31 1487

Bartolomeu Dias sets sail from Lisbon, Portugal with a small fleet on an expedition to find a sea route to India. He succeeded, reaching Africa's southern cape on February 4, 1488 and entering what it is now known as Mossel Bay, becoming the first European to sail around the southern tip of Africa.

Bartolomeu Dias - KUDOS 365 BIOGRAPHY SERIES

Bartolomeu Dias was a Portuguese navigator and explorer whose voyage around the southern tip of Africa helped open the sea route between Europe and Asia. Little is known with certainty about his early life, but he served the Portuguese crown during an era when Portugal was steadily exploring the Atlantic coast of Africa in search of trade, geographic knowledge, and a maritime route to the Indian Ocean.

In 1487, King João II sent Dias southward along the African coast. His expedition sailed beyond the limits reached by earlier Portuguese voyages and, after being driven by storms, rounded the southern end of Africa without initially realizing it. When Dias later turned east and then north, he had proved that the Atlantic and Indian Oceans were connected by a navigable route around Africa.

Dias wanted to continue farther, but his crew pressed for a return to Portugal. On the voyage back, he saw the cape that marked Africa’s southern turning point. He is traditionally associated with naming it the Cape of Storms, reflecting the dangerous weather encountered there. The Portuguese king later favored the more hopeful name Cape of Good Hope, because the discovery suggested a sea route to India.

Dias’s achievement did not immediately complete Portugal’s goal, but it made later success possible. Vasco da Gama used the route around the Cape a decade later to reach India, transforming European trade and expanding Portuguese influence in the Indian Ocean. Dias also participated in later Portuguese expeditions, including the fleet associated with Pedro Álvares Cabral.

In 1500, Dias died when storms struck Cabral’s fleet near the Cape of Good Hope. His death occurred close to the waters that had made him famous. His legacy rests on a single decisive voyage: by rounding southern Africa, he changed European geographic understanding and helped redirect global maritime history.

1591 CE, July 15

Spanish forces defeat a fleet of English privateers on July 15, 1591 at the Battle of Gelves (Also known as the Battle of the Berlengas Islands), off the coast of Portugal, during the Anglo-Spanish War.

1733 CE, July 15

The Spanish ship San Jose y las Animas sinks off the coast of Florida, becoming a subject of treasure hunting.The wreck was located by treasure hunters in 1968, lying in about twenty-eight feet of water. The ship was carrying a substantial amount of treasure, estimated to be worth millions of pesos.

1799 CE, July 15

The Rosetta Stone is found in the Egyptian village of Rosetta, providing a key to deciphering ancient Egyptian hieroglyphs. The large inscribed stone fragment was uncovered by the French officer Pierre François Xavier Bouchard on a tributary of the Nile near the Mediterranean coast east of Alexandria where Napoleon’s forces were constructing fortifications. More

1903 CE, July 15

Ernest Pfennig, a Chicago dentist, orders the first Original Model A Ford car. The car is delivered a week later on July 23, 1903. A total of 1,750 cars were made from 1903 through 1904 and sold at an average price of $850. More

1918 CE, July 15

The Second Battle of the Marne starts during the First World War. It was the last major German offensive on the Western Front lasting a year and ending on August 6, 1919.

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