It appears from those who have written the history of Russia that neither native nor European authorities know anything about it before the latter half of the ninth century, and that the tenth century is nearing its end before anything like firm ground is reached. Their name is by this time quite familiar to the Arabic chroniclers, and Ibn al-Athir even takes the trouble to record the commencement of the conversion of the Russians to Christianity; according to him in the year 375, i.e. 985–6 a.d., the Byzantine emperors being besieged found it necessary to invoke the aid of the king of the Russians, and offered him their sister in marriage. She declined to marry one who was not of her religion, whence this Russian king adopted Christianity, and that was how the religion began to be propagated in his country. The date of the first conversion of a Russian king given by Morfill on the authority of a Russian chronicle is within two years of that assigned by Ibn al-Athir; the former 988, the latter apparently 986; and Ibn al-Athir is here following a contemporary record. The name Rūs, i.e. Russians, was already familiar to Ibn al-Athir's readers and indeed those of the authority whom he excerpts owing to their being mentioned by the popular poet Mutanabbi in his most celebrated poem, describing the victory won by the Hamdanide Saif al-daulah in 954 over a force mustered by the Byzantine general called the Domesticus, wherein according to the poet so many tribes and tongues were represented that a staff of interpreters was required.