Colgrim had obviously planned to meet Artur south of Lincoln, cutting him off from that city if he were defeated, and ensuring its fall.  And Baldulf, who was coasting on the lookout for the German reinforcements, was to cooperate by landing at the Wash so as to take Artur in the rear or right flank.  Colgrim, however, was a little too late, or Baldulf a little too soon, and Artur was able to drive the latter back into his ships at the mouth of the Glen before meeting Colgrim.  Then followed a four days' battle on the Dubglas, Colgrim probably expecting each day that Baldulf would come up, while Baldulf himself, in ignoracne of Colgrim's whereabouts, had sailed back to the Humber...
    Baldulf = Balduulf, a genuine Northumbrian name, but so rare that I have only found one instance of it (in Sweet's Old English Texts)... (The Academy, v.49, 1896)