the Bulgars removed to the Balkans; others remained in their native country on the shores of the Azov Sea, and were subjugated by the Khazars.  At the beginning of the 9th century, they marched northwards to the Volga and the Kama, and established the kingdom of Great Bulgaria.  Their chief city, Bolghar, was on the bank of the Volga, but the river runs now to the west; as the Kama also underwent a change in its course, it is possible that formerly Bolghar was built at the junction of the two rivers. (Cf. Reclus, Europe russe, p. 761.) The Bulgars were converted to Islam in 922.  Their country was first invaded by the Mongols under Subutai in 1223; this General conquered it in 1236, the capital was destroyed the following year, and the country annexed to the kingdom of Kipchak.  Bolghar was again destroyed in 1391 by Tamerlan.  In 1438, Ulugh Mohammed, cousin of Toka Timur, younger son of Juji, transformed this country into the khanate of Kazan, which survived till 1552.  It had probably been the capital of the Golden Horde before Sarai.

With reference to the early Christianity of the Bulgarians, to which Yule refers in his note, the Laurentian Chronicle (A.D. 1229), quoted by Shpilevsky, adduces evidence to show that in the Great City, i.e. Bulgar, there were Russian Christians and a Christian cemetery, and the death of a Bulgarian Christian martyr is related in the same chronicle as well as in the Nikon, Tver, and Tatischef annals in which his name is given. (Cf.  Shpilevsky, Anc. towns and other Bulgaro-Tartar monuments, Kazan, 1877, p. 158 seq.; Rockhill’s Rubruck, Hakl.  Soc. p. 121, note.) —­H.  C.]

The severe and lasting winter is spoken of by Ibn Folzan and other old writers in terms that seem to point to a modern mitigation of climate.  It is remarkable, too, that Ibn Fozlan speaks of the aurora as of very frequent occurrence, which is not now the case in that latitude.  We may suspect this frequency to have been connected with the greater cold indicated, and perhaps with a different position of the magnetic pole.  Ibn Fozlan’s account of the aurora is very striking:—­“Shortly before sunset the horizon became all very ruddy, and at the same time I heard sounds in the upper air, with a dull rustling.  I looked up and beheld sweeping over me a fire-red cloud, from which these sounds issued, and in it movements, as it were, of men and horses; the men grasping bows, lances, and swords.  This I saw, or thought I saw.  Then there appeared a white cloud of like aspect; in it also I beheld armed horsemen, and these rushed against the former as one squadron of horse charges another.  We were so terrified at this that we turned with humble prayer to the Almighty, whereupon the natives about us wondered and broke into loud laughter.  We, however, continued to gaze, seeing how one cloud charged the other, remained confused with it a while, and then sundered again.  These movements lasted deep into the night, and then all vanished.”