Sultán `Abdu'l-`Azíz, at the instigation of his Prime Minister, Ali Pasha, issued a firmán condemning Bahá'u'lláh to perpetual banishment. [BKG283–4; GPB179, 186; RB2:401–2]
See RB2:402 for a list of those included in the edict.
BKG261, GPB181 and RB2:403 indicate that it was not until the party reached Gallipoli that they were informed that their ultimate destination was `Akká.
BBD40 says that it was because of the disloyal Mírzá Yahyá's plotting against Bahá`u`lláh that the Turkish authorities condemned Him to perpetual imprisonment in `Akká.