Saint Andrew the Apostle was an apostle of Jesus according to the New Testament. He is referred to in the Orthodox tradition as the First-Called. According to Orthodox tradition, the apostolic successor to Andrew is the Patriarch of Constantinople. Tradition regarding the early Christian history of Ukraine holds that the apostle Andrew preached on the southern borders of modern-day Ukraine, along the Black Sea. Legend has it that he traveled up the Dnieper River and reached the future location of Kyiv, where he erected a cross on the site where the Saint Andrew's Church of Kyiv currently stands and where he prophesied the foundation of a great Christian city. Because of this connection to Kyiv, Andrew is considered to be the patron saint of the two East Slavic nations descended from the Kievan Rus: Ukraine and Russia, the latter country using the Saint Andrew's Cross on its naval ensign.