The history of Arabia and its inhabitants naturally divides itself into two distinct and even dissimilar periods, that, namely, which preceded the era of Mohammed, and that which followed it. Each of these two periods, though comprising in its extent several minor phases and fluctuations, now of advance, now of retrogression, bears, however, a well-marked general character of its own. The first of the two periods is distinguished as one of local monarchies and federal governments; the latter commences with theocratic centralisation dissolving into general anarchy. The first dawning gleams of anything that deserves to be called history disclose Arabia wholly, or nearly so, under the rule of a race of southern origin; the genuine, or, as they are sometimes termed from a mythical ancestor Kahtan, the Kahtanee Arabs. These, again, we find subdivided into several aristocratic monarchical governments, arranged so as to form a broad framework or rim around the central wilds of the peninsula. Oldest and chiefest among the Arab monarchies was that of Yemen; its regal residence is said to have been in the now abandoned town of Mareb, in the extreme south. After a devastating inundation, referred with some probability to the first century of the Christian era, the seat of government was removed from the ruins of Mareb to Sana, a city which has continued the metropolis of Yemen to the present day. The Yemenite kings, descendants of Kahtan and Himyar (the dusky), a name denoting African origin, and each adorned with the reiterated surname of “Tobba,” a word of African etymology, and signifying “powerful,” are said to have reigned, with a few dynastic interruptions and palace revolutions, for about twenty-five hundred years, during which long period they commanded the direct obedience of the entire southern half of the peninsula; while, by their tribute-collectors, and by chiefs of kindred or delegated authority, they indirectly governed the northern. One of these monarchs is asserted, though historical criticism will hardly admit the assertion for fact, to have subdued the whole of central Asia, and even to have reached the boundaries of China; while another anticipated, so runs the story, the later and more authentic conquests of his race on the north African continent. In both these cases Arab chroniclers seem to have appropriated for their own rulers, not without some additional exaggerations, the glories and exploits of the Egyptian kings. But that theirs was a vigorous and in some respects a civilised government is attested alike by the literary and the architectural relics of their time. Their sovereignty was at last overthrown, 529 (A.D.) by an Abyssinian invasion, and was re-established in 603 A.D. as a dependency of the Persian Empire, till in the year 634 it was finally absorbed by Mohammedan conquest. [Sidenote: [100-500 A.D.]]