shall mention here only Ḥamza of Iṣfahán, the eighth book of whose Annals (finished in 961 A.D.) provides a useful sketch, with brief chronological details, of the Tubba‘s or Ḥimyarite kings of Yemen. [Sidenote: Ya‘rub.] [Sidenote: Ḥimyar and Kahlán.] Qaḥṭán, the ancestor of the Southern Arabs, was succeeded by his son Ya‘rub, who is said to have been the first to use the Arabic language, and the first to receive the salutations with which the Arabs were accustomed to address their kings, viz., "_In‘im ṣabáḥan_" ("Good morning!") and "_Abayta ’l-la‘na_" ("Mayst thou avoid malediction!"). His grandson, ‘Abd Shams Saba, is named as the founder of Ma’rib and the builder of the famous Dyke, which, according to others, was constructed by Luqmán b. ‘Ád. Saba had two sons, Ḥimyar and Kahlán. Before his death he deputed the sovereign authority to Ḥimyar, and the task of protecting the frontiers and making war upon the enemy to Kahlán. Thus Ḥimyar obtained the lordship, assumed the title Abú Ayman, and abode in the capital city of the realm, while Kahlán took over the defence of the borders and the conduct of war.[45] Omitting the long series of mythical Sabæan kings, of whom the legend has little or nothing to relate, we now come to an event which fixed itself ineffaceably in the memory of the Arabs, and which is known in their traditions as _Saylu ’l-‘Arim_, or the Flood of the Dyke. [Sidenote: The Dam of Ma’rib.] Some few miles south-west of Ma’rib the mountains draw together leaving a gap, through which flows the River Adana. During the summer its bed is often dry, but in the rainy season the water rushes down with such violence that it becomes impassable. In order to protect the city from floods, and partly also for purposes of irrigation, the inhabitants built a dam of solid masonry, which, long after it had fallen into ruin, struck the imagination of Muḥammad, and was reckoned by Moslems among the wonders of the world.[46] That their historians have clothed the bare fact of its destruction in ample robes of legendary circumstance is not surprising, but renders abridgment necessary.[47] [Sidenote: Its destruction announced by portents.]