Hereward the Last of The English by Charles Kingsley

Of Hereward's doings for the next few months naught is known. He may very likely have joined Siward in the Scotch war. He may have looked, wondering, for the first time in his life, upon the bones of the old world, where they rise at Dunkeld out of the lowlands of the Tay; and have trembled lest the black crags of Birnam should topple on his head with all their pines. He may have marched down from that famous leaguer with the Gospatricks and Dolfins, and the rest of the kindred of Crinan (abthane or abbot, -- let antiquaries decide), -- of Dunkeld, and of Duncan, and of Siward, and of the outraged Sibilla. He may have helped himself to bring Birnam Wood to Dunsinane, "on the day of the Seven Sleepers," and heard Siward, when his son Asbiorn's corpse was carried into camp, [Footnote: Shakespeare makes young Siward his son. He, too, was slain in the battle: but he was Siward's nephew.] ask only, "Has he all his wounds in front?"

He may have seen old Siward, after Macbeth's defeat (not death, as Shakespeare relates the story), go back to Northumbria "with such booty as no man had obtained before," -- a proof, if the fact be fact, that the Scotch lowlands were not, in the eleventh century, the poor and barbarous country which some have reported them to have been.