Constantine the Great
272-337
Constantine the Great’s reign marked the shift from pagan to Christian Rome. He rose to power amid civil wars, defeating rivals like Maxentius at the Battle of Milvian Bridge in 312 after a vision of a Christian cross and the words “In this sign, conquer.” He became the first emperor to convert to Christianity, ending persecution of Christians with the Edict of Milan, which granted religious tolerance. He founded Constantinople as the new Christian capital of the empire. Constantine supported the Church, presided over the Council of Nicaea to settle doctrinal disputes, and shaped Christianity’s future, though he was baptized only on his deathbed.
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Photo of the colossal statue of Roman Emperor Constantine I at the Capitoline Museums in Rome, showing the marble sculpture’s upper body.
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Theodosius I
347-395
Theodosius I was the last emperor to rule a united Rome. He was made Eastern emperor in 379 after the Roman defeat at Adrianople. He made peace with the Visigoths, allowing them to settle as allies. A devout Christian, Theodosius declared Nicene Christianity the official state religion via the Edict of Thessalonica and banned pagan sacrifices, marking the end of official Roman paganism. He supported the Council of Constantinople against heresies. After the massacre in Thessalonica, he submitted to public penance demanded by Bishop Ambrose. Upon his death, the empire split permanently between his sons Arcadius (East) and Honorius (West).
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Photograph of a marble bust of Roman Emperor Theodosius I (“the Great”) from the Aphrodisias Archaeological Museum in Aydın, Turkey.
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Council of Nicaea
325
The First Council of Nicaea was the first ecumenical council of the Christian Church. About 300 bishops attended to resolve major disputes threatening Church unity. The chief issue was Arianism, taught by priest Arius, who claimed Jesus Christ was created by God the Father and not fully divine or eternal. The council firmly rejected Arianism, affirming that the Son is "of the same substance“ as the Father—truly God. They produced the original Nicene Creed, a statement of core Christian beliefs still recited today. They also set rules for Easter's date and Church organization. This gathering shaped orthodox Christianity and marked imperial involvement in doctrine.
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Icon from the Mégalo Metéoron Monastery (Greece) depicting the First Ecumenical Council of Nicaea (325 AD) with the heretic Arius at the bottom.
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Founding of Constantinople
330
Constantine founded Constantinople on the site of the ancient Greek city of Byzantium. He chose this strategic location for its excellent defenses, control of trade routes between Europe and Asia, and access to both the Black Sea and Mediterranean. He refounded the city as "New Rome," enlarging it with massive walls, forums, palaces, churches, and a hippodrome. He dedicated it on May 11, 330, with ceremonies blending Roman and Christian elements. Constantinople became the empire's new capital, shifting power eastward and becoming a thriving Christian center that lasted over 1,000 years as the Byzantine Empire's heart.
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Map of Byzantine Constantinople showing the city’s layout and walls at the historic capital of the Eastern Roman Empire.
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Old St. Peter's Basilica
324-330
Old St. Peter's Basilica was a massive church commissioned by Emperor Constantine the Great on Vatican Hill, over the tomb of Saint Peter, Jesus' chief apostle. As the first grand public Christian basilica after centuries of persecution, it symbolized Christianity's new imperial favor. With a vast five-aisled nave, atrium, and central shrine, it became a major pilgrimage site. It hosted key events, including Charlemagne's coronation as Holy Roman Emperor in 800 AD. Deteriorating by the 1400s, it was demolished starting 1506 for the current Renaissance St. Peter’s. It remains a cornerstone of Christian history.
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Drawing of Old St. Peter’s Basilica in Rome (c. 1450 reconstruction), created by Henry William Brewer in 1891.
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Church of the Holy Sepulchre
335
The Church of the Holy Sepulchre in Jerusalem is Christianity's holiest site, which encompasses Golgotha (where Jesus was crucified) and his burial tomb (where he rose).Built by Emperor Constantine in 326 AD after his mother Helena identified the locations, it was dedicated in 335. Destroyed in 1009 by Caliph al-Hakim and rebuilt by Crusaders in the 12th century, the current structure reflects layers of history. Shared uneasily by multiple denominations (Greek Orthodox, Catholic, Armenian, etc.), it remains the focal point of Easter celebrations and pilgrimages worldwide.
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Photograph of the Church of the Holy Sepulchre (Jerusalem) exterior, cropped to focus on the area of the original church structure.
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Fishing Reel
300s
The earliest evidence for fishing reels dates to ancient China. A Chinese text, "Lives of Famous Immortals", provides the first written mention of a device resembling a reel, described in a story of a fisherman. These were likely simple mechanisms—possibly wooden spools or winch-like tools—for storing and retrieving line on rods. No archaeological reels from this era survive, and the reference is somewhat speculative, but historians accept it as the origin. Clearer depictions appear later, in Song Dynasty art (1195 AD painting by Ma Yuan showing a rod with reel).Reels remained rare and basic until European developments in the 17th century.
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Photo of a historic Nottingham fishing reel (wide‑arbour design) from the 1800s used in coarse and fly fishing.
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Lateen Sail
300s
The lateen sail emerged as a refinement of far older Egyptian sailing traditions, especially the angled fore-and-aft rigs long used on the Nile. Mediterranean shipbuilders transformed this concept into a triangular sail set on a long yard, enabling ships to sail closer to the wind—something square sails could not do. This innovation revolutionized maneuverability, trade, and naval warfare. The lateen sail became central to Byzantine and Islamic seafaring and later shaped medieval European navigation, forming a critical link to the ocean-going vessels of the Age of Exploration.
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Photo of a Mozambican dhow ferrying passengers from Inhambane to Maxixe under a lateen sail on coastal waters.
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