Imam Yayha's attempt to lay claim to Najran and southern Asir, initiated the previous year, elicited a predictable response from Ibn Saud. While both these regions were clearly within Ibn Saud's sphere of influence, he had made no great effort to integrate them formally into his Kingdom, preferring to leave them as semi-autonomous sheikdoms and as a useful buffer between his as yet undefined southern border and the Yemen. Imam Yahya's decision to lay claim to these territories demanded action.
Leading a troop of Saudi tribesmen, Khalid bin Luay drove the Yemenis out of Najran and formally annexed the land in the name of Ibn Saud.
Any hope that Imam Yayha would accept this reverse gracefully proved ill-founded. In response, he re-asserted his claim to southern Asir with renewed vigor. What had started as a mild disagreement over some ill-defined territory was fast growing into a sufficient cause for war.
