Constantinople
From Bahaipedia
Constantinople (Turkish: İstanbul) modern day Istanbul. It was the capital of the (Christian) Byzantine Empire until the Ottomans took it over and made it their capital. They renamed it Istanbul. Bahá’u’lláh, along with His family and a group of other Bábís and Bahá’ís were imprisoned in Constantinople for 4 months. In Constantinople, the Persian authorities, along with the Ottoman ones, tried to make life as difficult as possible for Bahá’u’lláh and the exiles. Scared of His influence, they later moved them to Adrianople, a remote city in the Ottoman Empire. From Adrianople (Edirne), Bahá’u’lláh would eventually go on to the infamous prison city of ‘Akká.
This is a soft redirect, see Istanbul.