Whatever the real events of Marwan's campaigns, warfare between the Khazars and the Arabs ceased for more than two decades after 737. Arab military activity in the Caucasus continued until 741, with Marwan launching repeated expeditions against the various principalities of the northern Caucasus. Blankinship emphasizes that these campaigns appear to have been closer to raids, designed to seize plunder and extract tribute to ensure the upkeep of the Arab army, rather than attempts at permanent conquest. On the other hand, the British orientalist Douglas M. Dunlop considered that Marwan came "within an ace of succeeding" in his conquest of Khazaria, and that he "apparently intended to resume operations against the "khagan" at a later date", but this never materialized.