The first cathedral is commonly recognized to be the Cathedral of Trier, located in Trier, Germany. This architectural marvel was originally built in the 4th century as a palace church for the Roman Emperor Constantine the Great. Over the centuries, it has undergone various renovations and expansions, reflecting different architectural styles.
The significance of Trier Cathedral extends beyond its age; it is a key symbol of early Christianity in Europe. As the oldest cathedral in Germany, it houses numerous relics and is a testament to the evolution of ecclesiastical architecture. Visitors today can appreciate its intricate designs and rich history, which have made it a UNESCO World Heritage site.