Journey to Istanbul, the magnificent city straddling Europe and Asia, where Byzantine emperors once safeguarded Christianity's most precious relics. This former Constantinople houses ancient churches and sacred collections that claim to preserve fragments of the True Cross, brought to the city by Helena, mother of Emperor Constantine. Follow in the footsteps of Expedition Unknown as you explore these hallowed sites where faith, history, and mystery converge in one of the world's most captivating cities.
Istanbul, straddling the Bosphorus strait between Europe and Asia, is Turkey's largest city with a population exceeding 15 million and covers an area of 5,461 square kilometers. The city evolved from ancient Byzantium into Constantinople in 330 AD, serving as capital of the Roman/Byzantine Empire, the Latin Empire, and the Ottoman Empire over nearly 16 centuries. Its historic center is a UNESCO World Heritage Site lined with palaces, churches, and imperial mosques that reflect its layered imperial past. Gates investigated the city in "True Cross of Christ," exploring whether Byzantine churches and collections preserve authentic fragments of the cross on which Jesus was crucified, relics reportedly brought to Constantinople by Saint Helena, mother of Emperor Constantine, in the 4th century.
Greek colonists potentially founded Byzantium on the Sarayburnu promontory
City reestablished as Constantinople, becoming capital of the Roman Empire
Constantinople served as capital of the Latin Empire during the Crusades
Ottoman forces conquered Constantinople, transforming it into an Islamic capital
Republic of Turkey established with capital moved to Ankara; city later renamed Istanbul
Gates' Expedition Unknown investigates potential True Cross relics in Byzantine collections
Constantinople was instrumental in the advancement of Christianity during Roman and Byzantine times, and according to tradition, Saint Helena, mother of Emperor Constantine the Great, brought fragments of the True Cross to the newly established Christian capital in the 4th century. The city's Byzantine churches became repositories for significant Christian relics during the empire's thousand-year reign, attracting pilgrims from across the Christian world. Historians generally acknowledge that Constantinople housed numerous claimed True Cross fragments, though authenticating any specific relic to the actual crucifixion remains beyond current scientific capability.
The challenge Gates faced in Istanbul reflects the complex history of Christian relics in a city that transitioned from Byzantine Christian capital to Ottoman Islamic stronghold in 1453. Many Byzantine churches were converted to mosques or fell into disrepair during the Ottoman period, and relics were dispersed, lost, or moved to European collections during the turbulent centuries following the conquest. The Fourth Crusade's sack of Constantinople in 1204 also resulted in the scattering of countless relics westward to Venice, Rome, and other European cities.
Modern scholars approach True Cross relics with appropriate skepticism, noting that the sheer number of claimed fragments dispersed across Europe and the Middle East would require a forest of crosses if all were genuine. Authentication methods remain limited — carbon dating can confirm age but cannot prove association with a specific historical event or individual. Gates' investigation highlighted this fundamental challenge: even in a city as historically rich as Istanbul, definitive proof of relic authenticity remains elusive.
The episode's exploration of Istanbul's Byzantine heritage underscored the city's unique position as a living museum of multiple empires. While Gates may not have found conclusive evidence authenticating specific True Cross fragments, the investigation showcased how Constantinople's role as a Christian capital created the conditions for such relics to have been housed there, even if their current whereabouts and authenticity remain matters of faith rather than forensic certainty.
Istanbul is the only major city in the world that straddles two continents, with approximately two-thirds of its population living on the European side and one-third on the Asian side.
The city served as capital of three successive empires — Roman/Byzantine, Latin, and Ottoman — over nearly 16 centuries from 330 to 1922.
Istanbul straddles the Bosphorus, one of the world's busiest waterways, connecting the Black Sea to the Sea of Marmara and the Mediterranean.
In 2024, Euromonitor International ranked Istanbul as the second most visited city in the world.
Istanbul is highly accessible to international visitors, with two major airports and a well-developed tourism infrastructure. Byzantine heritage sites including the Hagia Sophia, Topkapi Palace, and numerous churches-turned-museums are generally open to visitors, though current operating hours and access policies should be confirmed before visiting. The city's historic peninsula is walkable, and public transportation connects major sites.
Istanbul itself is Turkey's largest city and primary international gateway.
Spring (April-May) and fall (September-October) offer mild weather and smaller crowds compared to the summer peak season. Winter can be rainy and cold, though the city remains vibrant year-round.
UNESCO World Heritage Site (Historic Areas of Istanbul)
Holy Land
The Holy Land sites connect directly to the True Cross investigation, as Jerusalem is the origin point for relics that Helena reportedly brought to Constantinople.
St. Mark's Cathedral
St. Mark's Cathedral in Venice houses Byzantine relics and treasures looted during the Fourth Crusade's 1204 sack of Constantinople, representing the dispersal of the city's Christian heritage.
Italy (St. Nicholas sites)
Italy's St. Nicholas investigation sites reflect similar Gates explorations of Christian relic authenticity and the movement of sacred objects across the Mediterranean world.
Best time to visit: Visit during spring (April-May) or fall (September-October) for pleasant weather and fewer crowds when exploring the historic religious sites.
Travel tip: Purchase the Istanbul Museum Pass for discounted entry to multiple sites and skip-the-line access to popular attractions like the Hagia Sophia.
Historical data sourced from Wikipedia