 After Siba'i's imprisonment, under Isam al-Attar's leadership the Brotherhood developed into the ideological antithesis of Ba'athist rule.However, the Ba'ath Party's organizational superiority worked in its favor; with Attar's enforced exile, the Muslim Brotherhood was in disarray.It was not until the 1970s that the Muslim Brotherhood established a clear, central collective authority for its organization under Adnan Saad ad-Din, Sa'id Hawwa, Ali Sadr al-Din al-Bayanuni and Husni Abu.