One of its towers was known to exist since the beginning of the 20th century, but a thorough research upon this monument was only possible between 1987 and 1998. This is where the road coming from Histria, another important Greek-Roman city on the Romanian littoral, entered in the fortified urban area of Tomis. It was an imposing monument, part of the Roman-Byzantine fortification which protected the city on its continental side. It was not the only entrance, but it certainly was the most important one. It has the largest opening (about 10 meters wide), and the most strategic and complex plan. It was built at the beginning of the 4th century AD, when many urban features of Tomis were changed and renewed, and it was meant to protect an important part of the city, which functioned on the outskirts of the city before its construction. The main Christian edifice, which probably was the bishopric basilica of Tomis, was built in the vicinity of this gate.