Yenişehir Kapı (Iznik)
Yenişehir Gate, the southern entrance gate of the ancient city of Nikaia, is on the road connecting Nikaia to the other cities of the Bithynia Province, Prusa ad Olympum/Prusa (Bursa) and Apameia (Mudanya) and other cities of the Asia Province. Yenişehir gate is similar to the Istanbul and Lefke gates, which are the northern and eastern gates of the city. 

The city of Nikaia entered an intense construction process after it came under the auspices of the Roman Empire. The first phase of the Yenişehir Gate, which is among these construction activities, is dated to the Flavian period (AD 69-96). During this period, city entrances were decorated with aesthetic architectural elements in order to show and symbolically indicate the wealth and prestige of the city. Honorary arches were built at the southern entrance of the city for propaganda purposes. This architectural element, which is also found at the northern and eastern entrances of the city, differs slightly at the southern entrance; The honorary arch, created with marble block pieces, has a single arched central passage. The building in question welcomed those entering the city as a symbolic structure as the Arch of Honor during the pax Romana (Roman Peace) period, which lasted nearly 200 years. Its function was changed when this period ended as a result of the invasion by the Goths. The Arch of Honor, combined with the city wall built between 253-270 AD (periods of Emperors Gallienus and Gothicus), was transformed into a structure for defensive purposes. A tower was built on the east side of the Honor Arch to strengthen the fortifications. In addition, on the side of the gate facing the city center, an entrance was built, of which only foundation ruins are visible today, and a closed courtyard was created. The city walls and gates underwent various repairs until the Laskarid period. In the 13th century AD, a second city wall was built in front of the existing city wall in order to strengthen the defensive structures. A third door with an arched central passage was created almost on the same line as the early door axis. Brick and rubble stone masonry was used in the city wall and gate. In order to strengthen the defense, a bastion was built on both sides of the gate.