In Autumn 1995 the Saudi-Yemeni border constituted Arabia´s last indeterminate territorial limit, with the exception of its westernmost stretches, from the Red Sea to Najran, settled by a treaty of 1934. Talks between the Riyadh and Sana´a Governments on the unresolved border question had been intermittently in progress since July 1992. In February 1995 the two states signed a memorandum of understanding reaffirming the provision of the 1934 Treaty of Taif. The Treaty was formally renewed in June 1995, providing for a re-demarcation of the westernmost boundary and establishing a procedural framework for the settlement of the remainder of the boundary further east. The documents provide a wide historical context in which to view the efforts to finalise the political map of the south-western peninsula. Any settlement finally reached between Saudi Arabia and Yemen will need to take full account of critical factors which have shaped the history of their borderlands.