Siward or Sigurd is an important earl of 11th-century northern England.
The Old Norse nickname Digri and its Latin translation Grossus ("the stout") are given to him by near-contemporary texts.
Siward is probably of Scandinavian origin, perhaps a relative of Earl Ulf, and emerges as a powerful regional strongman in England during the reign of Cnut ("Canute the Great", 1016–1035).
Cnut is a Scandinavian ruler who conquered England in the 1010s, and Siward is one of the many Scandinavians who come to England in the aftermath of that conquest.
Siward subsequently rises to become sub-ruler of most of northern England.
From 1033 at the latest, Siward is in control of southern Northumbria, that is, present-day Yorkshire, governing as earl on Cnut's behalf.
He entrenches his position in northern England by marrying Ælfflæd, the daughter of Ealdred, Earl of Bamburgh.
After killing Ealdred's successor Eadulf in 1041, Siward gains control of all Northumbria.
He exerts his power in support of Cnut's successors, kings Harthacnut and Edward, assisting them with vital military aid and counsel.
He probably gains control of the middle shires of Northampton and Huntingdon by the 1050s, and there is some evidence that he spread Northumbrian control into Cumberland.
In the early 1050s Earl Siward turns against the Scottish ruler Mac Bethad mac Findlaích ("Macbeth").
Despite the death of his son Osbjorn, Siward defeats Mac Bethad in battle in 1054.
More than half a millennium later, the Scotland adventure earns him a place in William Shakespeare's Macbeth.
Siward dies in 1055, leaving one son, Waltheof, who will eventually succeed to Northumbria.
St Olave's church in York and nearby Heslington Hill are associated with Siward.
