The Basilica of Constantine (German: Konstantinbasilika) or Aula Palatina at Trier, Germany, is a Roman palace basilica, that was built by the emperor Constantine (306–337 AD) at the beginning of the 4th century.
Today it is a World Heritage Site and contains the largest extant hall from antiquity (see List of ancient roofs). The room has a length of 67 m, a width of 26.05 m and a height of 33 m.
The Aula Palatina was built around 310 AD as a part of the palace complex. Originally it was not a free standing building but had other smaller buildings attached to it, such as a forehall, an entrance vestibule and some service buildings. The Aula Palatina was equipped with a floor and wall heating system (hypocaust).
During the medieval ages it was used as the residence for the bishop of Trier. For that the apse was redesigned into living quarters and pinnacles were added to the top of its walls. In the 17th century the archbishop Lothar von Metternich constructed his palace just next to the Aula Palatina and incorporating it into his palace some major redesign was done. Later int the 19th century Frederick William IV of Prussia ordered the building to be restored to its original Roman state, which was done under the supervision of the military architect Carl Schnitzler. In 1856 the Aula Palatina became a Protestant church. In 1944 the building burned due to an air raid of the allied forces during World War II. When it was repaired after the war, the historical inner decorations from the 19th century were not reconstructed, so that the brick walls are visible from the inside as well.