Sigeferth (died 1015) was, along with his brother Morcar, described by the Anglo-Saxon Chronicle

Anglo-Saxon Chronicle

The Anglo-Saxon Chronicle is a collection of annals in Old English chronicling the history of the Anglo-Saxons. The original manuscript of the Chronicle was created late in the 9th century, probably in Wessex, during the reign of Alfred the Great...

as "chief thegn

Thegn

The term thegn , from OE þegn, ðegn "servant, attendant, retainer", is commonly used to describe either an aristocratic retainer of a king or nobleman in Anglo-Saxon England, or as a class term, the majority of the aristocracy below the ranks of ealdormen and high-reeves...

 of the Seven Burghs".

According to the 12th century chronicle of John of Worcester

John of Worcester

John of Worcester was an English monk and chronicler. He is usually held to be the author of the Chronicon ex chronicis.-Chronicon ex chronicis:...

, Sigeferth and Morcar

Morcar (died 1015)

Morcar was a thane of King Æthelred the Unready. He was given lands in Derbyshire in 1009 including Weston-on-Trent, Crich and Smalley by King Æthelred, 1011 and 1012. He was also given the freedom from the three common burdens. He and his brother were murdered in 1015...

 were the sons of one Earngrim who is otherwise unrecorded. The Seven Burghs of which they were said to be the chief men are believed to have been the Five Burghs

Five Burghs

The Five Boroughs or The Five Boroughs of the Danelaw were the five main towns of Danish Mercia . These were Derby, Leicester, Lincoln, Nottingham and Stamford...

—Derby

Derby

Derby , is a city and unitary authority in the East Midlands region of England. It lies upon the banks of the River Derwent and is located in the south of the ceremonial county of Derbyshire. In the 2001 census, the population of the city was 233,700, whilst that of the Derby Urban Area was 229,407...

, Leicester

Leicester

Leicester is a city and unitary authority in the East Midlands of England, and the county town of Leicestershire. The city lies on the River Soar and at the edge of the National Forest...

, Lincoln

Lincoln, Lincolnshire

Lincoln is a cathedral city and county town of Lincolnshire, England.The non-metropolitan district of Lincoln has a population of 85,595; the 2001 census gave the entire area of Lincoln a population of 120,779....

, Nottingham

Nottingham

Nottingham is a city and unitary authority in the East Midlands of England. It is located in the ceremonial county of Nottinghamshire and represents one of eight members of the English Core Cities Group...

 and Stamford

Stamford, Lincolnshire

Stamford is a town and civil parish within the South Kesteven district of the county of Lincolnshire, England. It is approximately to the north of London, on the east side of the A1 road to York and Edinburgh and on the River Welland...

—together with Torksey and York

York

York is a walled city, situated at the confluence of the Rivers Ouse and Foss in North Yorkshire, England. The city has a rich heritage and has provided the backdrop to major political events throughout much of its two millennia of existence...

. These were among the chief towns of the northern part of the Danelaw

Danelaw

The Danelaw, as recorded in the Anglo-Saxon Chronicle , is a historical name given to the part of England in which the laws of the "Danes" held sway and dominated those of the Anglo-Saxons. It is contrasted with "West Saxon law" and "Mercian law". The term has been extended by modern historians to...

.