For the last few centuries, the history of South Yemen 1 has been shaped by the interaction of two conflicting forces. Its highly conservative and rigidly stratified society together with its quasi-tribal, decentralized and unstable government was a strong inhibitor to change. But the country has a unique geo-political position abutting the straits of Bāb al-Mandab, the shores of the Indian Ocean and the Red Sea, the important port of Aden located at this junction and the presence of the British there from 1839, exercised a countervailing pressure for innovation and change. The stability of South Yemeni politics was related to the current interaction between these two conflicting forces – the conservative and the innovative — and the degree of balance between them.