Beyoğlu is a district located on the European side of İstanbul, Turkey, separated from the old city by the Golden Horn. It was known as Pera during the Middle Ages, and this name remained in common use until the mid-20th century and the ethnic cleansing of its large Greek population.
According to the prevailing theory, the Turkish name of Pera, Beyoğlu, is a modification by folk etymology of the Venetian ambassadorial title of Bailo, whose palazzo was the most grandiose structure in this quarter. The informal Turkish-language title Bey Oğlu was originally used by the Ottoman Turks to describe Lodovico Gritti, Istanbul-born son of Andrea Gritti, who was the Venetian Bailo in Istanbul during the reign of Sultan Bayezid II and was later elected Doge of Venice in 1523. Bey Oğlu thus referred to Lodovico Gritti, who established close relations with the Sublime Porte, and whose mansion was near the present-day Taksim Square. Located further south in Beyoğlu and originally built in the early 16th century, the "Venetian Palace" was the seat of the Bailo.