The most creditable military effort of the many in which his sword had been drawn, and that which redounded the most to his glory, was the last of his life. In 1054, he was sent by King Eadwarde in command of an expedition into Scotland against the usurper, Macbeth, in favour of the young Prince, Malcolm Canmore, son of the murdered King Duncan. He was now the father of two sons by his first wife—Æthelfleda—Osbert, now approaching manhood, and Waltheof, a boy, some years younger. The former he took with him to Scotland, to initiate him in the then deemed glorious art of war; and a brave young fellow he proved himself to be, a worthy scion of the old stock. Siward attacked Scotland by land and sea, met the usurper and defeated him in a pitched battle, after which he caused Malcolm to be proclaimed King. It is sometimes stated that Macbeth was slain in the battle, which was not the case, as he escaped and held out for three years, maintaining a desultory series of fights with Malcolm, but was eventually slain in 1057. His son Osbert fell in the battle, fighting bravely, and when the news was brought to him, he eagerly inquired if his wounds were in front, and when told they were, said that he could not but rejoice, such a death being worthy of one sprung from his loins.
Shakspeare, not always true to history, in his tragedy of "Macbeth" thus gives the death of "Young Siward," as he calls Osbert:—He meets with Macbeth on the field, and, after some bandying of words, they fight, and Macbeth falls, after which Osbert rushes into the thick of the fight, and falls himself. When Siward is told that all his son's wounds are in front, he exclaims—
"Why, then, God's soldier is he!
Had I as many sons as I have hairs,
I would not wish them to a fairer death:
And so his knell is tolled."
Prince Malcolm observes—
"He's worth more sorrow,
And that I'll spend for him."
To which Siward replies—
"He's worth no more.
They say he parted well, and paid his score,
And so God be with him."
Henry of Huntingdon, speaking of Siward's death, says—"And so he passed away, as he believed, to Valhalla, to rejoin the great warriors of his race who had gone before," seeming to intimate, founded on the misconception of his identity with the Viking Siward-Barn, that he died in the old Scandinavian faith of Woden, which was not true, as he lived and died a Christian, such as Christians were then. He is supposed to have founded a church in York, dedicated to St. Olaf, the martyred King of Norway, and connected with it a fraternity of monks, the name of which, in the reign of William II., was changed into that of St. Mary the Virgin, and eventually became the famous and wealthy abbey of after-times, with a mitred abbot. The ruins may now be seen in the grounds of the Museum.
He ruled his province with great firmness and some severity, necessary in his endeavours to curb the savage propensities of the people, and to establish a system of order and good government, and was bountiful to the Church, as some atonement, perhaps, for the crimes by which he rose to his high position.
Shortly after his return from his Scottish expedition, he was stricken with dysentery, which rapidly grew worse, and he lay in his vice-regal mansion at York without hope of recovery. When he felt his last moments approaching he suddenly started up from his couch and exclaimed, "Let me not die the death of a cow! If it be not my fate to die gloriously on the field of battle, as my brave boy, Osbert, has done, with all his wounds in front, at least let me die in the guise of a warrior. Don me my harness, place the helmet on my head, and gird my sword on my thigh. It were a shame and disgrace that I, who have faced death in so many fields, should die ignominiously in bed. Bring forth my battle-axe and shield, and place them by my side, that the ghosts of my warlike ancestry, who are looking down upon me now, may see me pass away from earth to join them in their everlasting home, with the semblance of the great warrior that I have been." And thus, seated on a chair, clothed in his armour, and supported in an upright posture by his attendants, he gave up the ghost, and was buried in his church of St. Olaf.