Next in importance to the kingdom of Yemen came the subsidiary monarchy of Hira, or more correctly Heerah, situated in the northeasterly province of Arabian Irak. Its kings, a collateral branch of the royal race of Sana, governed the western shore of the lower Euphrates, from the neighbourhood of Babylon down to the confines of Nejd, and along the coast of the Persian Gulf. The duration of their empire, founded in the second century after Christ, was 424 years. This kingdom paid an uncertain allegiance to their more powerful neighbours, the Persian despots; and from time to time exercised considerable influence over the turbulent tribes of central Arabia, till, like Yemen, it sank before the rising fortunes of Mohammed and his followers. A third monarchy, that of Ghassan, lorded it on the northwest over lower Syria and the Hedjaz; its independence was somewhat tempered with unequal alliances with the Roman, and subsequently the Byzantine Empire. It was founded in the first century of the Christian era, shortly after the flood of Mareb; and its duration, till subdued by the all-conquering prophet, exceeded six hundred years. A fourth government, that of Kindeh, detached itself from Irak early in the fifth century, and united under its sceptre the tribes of northerly Nejd and even those of Oman, for about 160 years. Its kings were, like those before mentioned, of Yemenite origin; but their rule was weak and disturbed by frequent wars. Much has been written by Arab authors regarding the great inundation, as they term it, of Arem or Mareb, possibly a tropical cyclone of more than ordinary destructiveness, like that of 1867 in the West Indies; and this event they love to assign as the proximate cause which dispersed the families of Yemen over northern Arabia, and led to the foundation of the kingdoms of Irak and Ghassan. But the reality of the events, physical or political, symbolised by the “flood of Arem” (a counterpart, after its fashion, of the biblical flood) cannot now be well deciphered.