Short answers, pulled from the story.
Greek colonists established a settlement named Tomis around 600 BC. This location offered a natural harbor and fertile land that supported early trade with inland regions via the Carasu valley.
Roman forces captured the region from the Odrysian kingdom in 29 BC, and Emperor Augustus banished Ovid to this remote town for the final eight years of his life starting in AD 8. He described the place in his poems Tristia and Epistulae ex Ponto as a war-stricken cultural wasteland on the remotest margins of the empire.
Avar forces besieged the city in the winter of 597/598 before it fell to the First Bulgarian Empire in 680. Byzantine troops under John I Tzimiskes retook control during the Rus-Byzantine War of 970-971, only for the Second Bulgarian Empire to seize it again in 1186.
Following independence in 1878, the population numbered just over 5,000 inhabitants and the city transformed into Romania's main seaport. The 2021 census recorded 263,688 inhabitants within city limits, representing a decrease from previous decades but still forming one of Romania's largest metropolitan areas.
On the 22nd of October 1916 Central Powers troops including German, Turkish, and Bulgarian forces occupied the city during World War I. The Treaty of Bucharest signed in May 1918 placed Constanța under joint control before Bulgaria took temporary rule until Allied liberation in September 1918.