Oslac of York

Oslac (fl. 966–975) is regarded as the first ealdorman (or earl) of York and its dependent territories. These included but may not have been limited to the southern half of Northumbria. His background is obscure because of poor source documentation. The latter has facilitated disagreement amongst historians regarding his family and ethnicity.

It is believed that he took over the position of ealdorman of York in 966, holding the position until his downfall in 975. He may have been the first ealdorman of southern—as opposed to a united—Northumbria, though an alternative tradition puts the division of Northumbria into two ealdormanries after his death. Little is known of his career as ealdorman, except for a legend that he escorted the Scottish king Kenneth II to the English royal court, and that he was expelled from England in 975. His life is unattested after this. He had one known son, but it is not clear if that son ever succeeded him.

Oslac's origins are unclear and no specific relationship with any previous known figure can be established from available sources. Oslac's name suggests to some historians that he was a Norseman. Dorothy Whitelock points out that the name Oslac is often an anglicisation of the Old Scandinavian name Áslákr, while the writers of the Biographical Dictionary of Dark Age Britain entry on Oslac comment that the name suggests an origin in the Danelaw, a suggestion supported by the fact that Thored, Oslac's son, held lands in Cambridgeshire.

On the other hand Oslac is also a genuine English name, and the common Os element Oslac's name shared with the name of Osulf of Bamburgh, previous ealdorman of York, points to a connection with the Bamburgh family of the English far north.

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