Ankara Treaty of Lausanne (1923), the Turkish nationalists replaced the Ottoman Empire with the Republic of Turkey on 29 October 1923. A few days earlier, Ankara had officially replaced Constantinople as the new Turkish capital city, on 13 October 1923. After Ankara became the capital of the newly founded Republic of Turkey, new development divided the city into an old section, called "Ulus", and a new section, called "Yenişehir". Ancient buildings reflecting Roman, Byzantine, and Ottoman history and narrow winding streets mark the old section. The new section, now centered on Kızılay Square, has the trappings of a more modern city:
Battle of Ankara through western Anatolia to the Aegean coast, where he besieged and took the city of Smyrna, a stronghold of the Christian Knights Hospitalers. The battle was catastrophic for the Ottoman state, fracturing what remained and bringing almost total collapse of the empire. This resulted in a civil war among Bayezid's sons. The Ottoman civil war continued for another 11 years (1413) following the Battle of Ankara. The battle is also significant in Ottoman history as being the only time a Sultan was captured in person. Battle of Ankara The Battle of Ankara or Angora was fought on 20 July 1402