Dyfnwal ab Owain (died 975) was a tenth-century King of Strathclyde. He was a son of Owain ap Dyfnwal, King of Strathclyde, and seems to have been a member of the royal dynasty of Strathclyde. At some point in the ninth- or tenth century, the Kingdom of Strathclyde expanded substantially southwards. As a result of this extension far beyond the valley of the River Clyde, the realm became known as the Kingdom of Cumbria. By 927, the kingdom seems to have reached as far south as the River Eamont.

Dyfnwal appears to have reigned between the 930s and the 970s. He is first attested in the 940s, when he is recorded associated with the ecclesiast Cathróe on the latter's journey to Continental Europe. At the midpoint of the decade, the Cumbrian kingdom was ravaged by the forces of Edmund, King of the English. Two of Dyfnwal's sons are said to have been blinded by the English, which could indicate that Dyfnwal had broken a pledge to his southern counterpart. One possibility is that he had harboured insular Scandinavian opponents of Edmund. The latter is recorded to have handed over control of the Cumbrian realm to Máel Coluim mac Domnaill, King of Alba. How much authority the Scots enjoyed over the Cumbrian realm is uncertain.

In 971, the reigning Cuilén mac Illuilb, King of Alba was slain by Rhydderch ap Dyfnwal. At some point after this act, Cuilén's eventual successor, Cináed mac Maíl Choluim, King of Alba, is recorded to have penetrated deep into Cumbrian territory, possibly as a retaliatory act. The following year, the reigning Edgar, King of the English held a remarkable assembly at Chester which numerous northern kings seem to have attended. Both Dyfnwal and his son, Máel Coluim, appear to have attended this assembly. The latter is styled King of the Cumbrians in the context of this meeting, which might indicate that Dyfnwal had previously abdicated the throne.

Dyfnwal is recorded to have died in 975 whilst undertaking a pilgrimage to Rome. Quite when he gave up the throne is unknown. One possibility is that Rhydderch had succeeded him before the killing of Cuilén. Another possibility is that the apparent retaliatory raid by Cináed marked the end of Dyfnwal's kingship. It is also possible that he held on to power until 973 or 975. In any event, Máel Coluim appears to have been succeeded by another son of Dyfnwal named Owain, who is recorded to have died in 1015. The later Owain Foel, King of Strathclyde, who is attested in 1018, may well be a grandson of Dyfnwal. Dyfnwal is likely the eponym of Dunmail Raise in England, and possibly Cardonald and Dundonald/Dundonald Castle in Scotland.

Background: the tenth century Cumbrian realm

For hundreds of years until the late ninth century, the power centre of the Kingdom of Al Clud was the fortress of Al Clud ("Rock of the Clyde").Charles-Edwards (2013b) p. 8; Clancy (2006). In 870, this British stronghold was seized by Irish-based Scandinavians,Edmonds (2015) p. 44; Charles-Edwards (2013b) pp. 9, 480; Clarkson (2012a) ch. 8 ¶ 21; Clarkson (2010) ch. 8 ¶ 20; Davies (2009) p. 73; Downham (2007) pp. 66, 142, 162; Clancy (2006); Ewart; Pringle; Caldwell et al. (2004) p. 8. after which the centre of the realm seems to have relocated further up the River Clyde, and the kingdom itself began to bear the name of the valley of the River Clyde, Ystrad Clud (Strathclyde).Driscoll, ST (2015) p. 5; Edmonds (2015) p. 44; Charles-Edwards (2013b) pp. 9, 480–481; Clarkson (2012a) ch. 8 ¶ 23; Clarkson (2010) ch. 8 ¶ 26; Clancy (2006); Ewart; Pringle; Caldwell et al. (2004) p. 8. The kingdom's new capital may have been situated in the vicinity of Partick.Driscoll, ST (2015) pp. 5, 7; Clarkson (2014) ch. 3 ¶ 13; Clarkson (2012a) ch. 8 ¶ 23; Clarkson (2012b) ch. 11 ¶ 46; Clarkson (2010) ch. 8 ¶ 22; Ewart; Pringle; Caldwell et al. (2004) pp. 8, 10. and Govan which straddle the River Clyde,Foley (2017); Driscoll, ST (2015) pp. 5, 7; Clarkson (2014) chs. 1 ¶ 23, 3 ¶ 11–12; Edmonds (2014) p. 201; Charles-Edwards (2013b) pp. 9, 480–481; Clarkson (2012a) ch. 8 ¶ 23; Clarkson (2012b) ch. 11 ¶ 46; Clarkson (2010) ch. 8 ¶ 22; Davies (2009) p. 73; Oram (2008) p. 169; Downham (2007) p. 169; Clancy (2006); Driscoll, S (2006); Forsyth (2005) p. 32; Ewart; Pringle; Caldwell et al. (2004) pp. 8, 10; Driscoll, ST (2003) pp. 81–82; Hicks (2003) pp. 32, 34; Driscoll, ST (2001a); Driscoll, ST (2001b); Driscoll, ST (1998) p. 112. The realm's new hinterland appears to have encompassed the valley and the region of modern Renfrewshire, which may explain this change in terminology.Charles-Edwards (2013b) pp. 480–481.

At some point after the loss of Al Clud, the Kingdom of Strathclyde appears to have undergone a period of expansion.Dumville (2018) p. 118; Driscoll, ST (2015) pp. 6–7; Edmonds (2015) p. 44; James (2013) pp. 71–72; Parsons (2011) p. 123; Davies (2009) p. 73; Downham (2007) pp. 160–161, 161 n. 146; Woolf (2007) p. 153; Breeze (2006) pp. 327, 331; Clancy (2006); Ewart; Pringle; Caldwell et al. (2004) pp. 9–10; Hicks (2003) pp. 35–37, 36 n. 78. Although the precise chronology is uncertain, by 927 the southern frontier appears to have reached the River Eamont, close to Penrith.Dumville (2018) pp. 72, 110, 118; Edmonds (2015) pp. 44, 53; Charles-Edwards (2013a) p. 20; Charles-Edwards (2013b) pp. 9, 481; Parsons (2011) p. 138 n. 62; Clarkson (2010) ch. 9 ¶ 10; Davies (2009) p. 73, 73 n. 40; Downham (2007) p. 165; Clancy (2006); Todd (2005) p. 96; Stenton (1963) p. 328. The catalyst for this southern extension may have been the dramatic decline of the Kingdom of Northumbria at the hands of conquering Scandinavians,Lewis (2016) p. 15; Charles-Edwards (2013b) pp. 9, 481–482; Breeze (2006) pp. 327, 331; Hicks (2003) pp. 35–36, 36 n. 78; Woolf (2001); Macquarrie (1998) p. 19; Fellows-Jensen (1991) p. 80. and the expansion may have been facilitated by cooperation between the Britons and the insular Scandinavians in the late ninth- or early tenth century.Charles-Edwards (2013b) pp. 481–482. Over time, the Kingdom of Strathclyde increasingly came to be known as the Kingdom of Cumbria reflecting its expansion far beyond the Clyde valley.Edmonds (2015) pp. 50–51; Molyneaux (2015) p. 15; Edmonds (2014); Davies (2009) p. 73; Edmonds (2009) p. 44; Clancy (2006).

Dyfnwal was a son of Owain ap Dyfnwal, King of Strathclyde.Clarkson (2014) ch. genealogical tables; Charles-Edwards (2013b) p. 572 fig. 17.4; Minard (2012); Clarkson (2010) ch. genealogical tables; Minard (2006); Macquarrie (1998) p. 6; Hudson (1994) p. 173 genealogy 6. The names of the latter and of his apparent descendants suggest that they were indeed members of the royal kindred of Strathclyde.Macquarrie (1998) pp. 14–15. Sons of Dyfnwal seem to include Rhydderch,Clarkson (2014) ch. genealogical tables; Charles-Edwards (2013b) p. 572 fig. 17.4; Clarkson (2010) ch. genealogical tables; Broun (2004d) p. 135 tab.; Macquarrie (1998) pp. 6, 16; Hudson (1994) p. 173 genealogy 6. Máel Coluim,Clarkson (2014) ch. genealogical tables; Charles-Edwards (2013b) p. 572 fig. 17.4; Clarkson (2010) ch. genealogical tables; Woolf (2007) p. 238 tab. 6.4; Broun (2004d) p. 135 tab.; Macquarrie (1998) pp. 6, 16; Hudson (1994) p. 173 genealogy 6. and Owain.Clarkson (2014) ch. genealogical tables; Charles-Edwards (2013b) p. 572 fig. 17.4; Clarkson (2010) ch. genealogical tables; Woolf (2007) p. 236, 238 tab. 6.4; Broun (2004d) pp. 128 n. 66, 135 tab. The name of Dyfnwal's son Máel Coluim is Gaelic, and may be evidence of a marriage alliance between his family and the neighbouring royal Alpínid dynasty of the Scottish Kingdom of Alba.Clarkson (2010) ch. 9 ¶ 44. Dyfnwal's father is attested in 934.Thornton (2001) p. 67 n. 65; Arnold (1882) p. 76 bk. 2 ch. 18; Stevenson, J (1855) p. 669 ch. 33. Although Dyfnwal's father may well be identical to the Cumbrian monarch recorded to have fought at the Battle of Brunanburh in 937,Naismith (2017) p. 281; Oram (2011) ch. 2; Duncan (2002) p. 23 n. 53; Macquarrie (1998) p. 14; Williams; Smyth; Kirby (1991) p. 103; Hudson (1994) p. 174 n. 7. the sources that note this king fail to identify him by name.Thornton (2001) p. 67 n. 65; Anderson, AO (1908) pp. 70–71, 71 n. 3; Arnold (1885) p. 93 ch. 83; Arnold (1882) p. 76 bk. 2 ch. 18; Stevenson, J (1855) pp. 482, 669 ch. 33. Dyfnwal's own reign, therefore, may have stretched from about the 930s to the 970s.Thornton (2001) p. 67.

Cathróe amongst the Cumbrians

Dyfnwal is attested by the tenth-century Life of St Cathróe, which appears to indicate that he was established as king by at least the 940s. According to this source, when Cathróe left the realm of Custantín mac Áeda, King of Alba at about this time, he was granted safe passage through the lands of the Cumbrians by Dyfnwal because the two men were related. Dyfnwal thereupon had Cathróe escorted through his kingdom to the frontier of the Scandinavian-controlled Northumbrian territory.Evans (2015) p. 150; Keynes (2015) p. 111; McGuigan (2015b) p. 98; Molyneaux (2015) p. 24, 24 n. 30; Clarkson (2014) chs. 1 ¶ 25, 6 ¶¶ 4–5; Edmonds (2014) pp. 205–206; Walker (2013) ch. 3 ¶ 51; Clarkson (2012a) ch. 10 ¶ 25; Clarkson (2010) ch. 9 ¶ 24; Broun (2004d) p. 127; Macquarrie (2004a); Macquarrie (2004b); Downham (2003) p. 27; Macquarrie (1998) pp. 15–16; Woolf (1998) p. 190; Hudson (1994) p. 174 n. 8; Anderson, AO (1922) p. 441; Skene (1867) p. 116; Colganvm (1645) p. 497 § xvii. The Life of St Cathróe locates this southern frontier to the of . One possibility is that this refers to Leeds. If correct, this could indicate that the Cumbrian realm stretched towards this settlement, and would further evince the general southward expansion of the kingdom.Molyneaux (2015) p. 24, 24 n. 30; Edmonds (2014) p. 206 n. 59; Hicks (2003) p. 38. Another possibility is that refers to Leath Ward in Cumberland,Edmonds (2014) p. 206 n. 59; Hicks (2003) p. 38. or to a settlement in the Lowther valley, not terribly far from where the River Eamont flows.Clarkson (2014) ch. 6 ¶ 5; Edmonds (2014) p. 206 n. 59; Clarkson (2012a) ch. 10 ¶ 25; Clarkson (2010) ch. 9 ¶ 24.