Rhun ab Arthgal was a ninth-century King of Strathclyde. He is the only known son of Arthgal ap Dyfnwal, King of Alt Clut. In 870, during the latter's reign, the fortress of Alt Clut was captured by Vikings, after which Arthgal and his family may have been amongst the mass of prisoners taken back to Ireland. Two years later Arthgal is recorded to have been slain at the behest of Causantín mac Cináeda, King of the Picts. The circumstances surrounding this regicide are unknown. The fact that Rhun seems to have been Causantín's brother-in-law could account for Causantín's interference in the kingship of Alt Clut.

The Viking destruction of the capital fortress of the Kingdom of Alt Clut appears to have brought about a reorientation of the kingdom towards the valley of the River Clyde. In consequence, the realm came to be known as the Kingdom of Strathclyde. Either Rhun or his father could have been the first kings of Strathclyde. In the years following the fall of Alt Clut, Rhun's realm may have endured periods of Pictish and Viking overlordship. Despite his kinship with the Pictish king, there is reason to suspect that the two clashed at some point.

It is unknown when Rhun's reign came to an end or when he died. One possibility is that he fell with Causantín, who seems to have been killed warring against the Vikings in 876. Certainly, Rhun's son, Eochaid, is recorded to have succeeded Causantín's successor, Áed mac Cináeda, King of the Picts, after 878. Whether Eochaid's succession reflects the end of Eochaid's reign and life is unknown.

Family

Rhun's patrilineal ancestry is evidenced by a pedigree preserved within a collection of tenth-century Welsh genealogical material known as the Harleian genealogies. According to this source, Rhun was a son of Arthgal ap Dyfnwal, King of Alt Clut, and descended from a long line of kings of Alt Clut.Guy (2016) pp. 6 tab. 1, 22–23; Clarkson (2014) chs. genealogical tables, 1 ¶ 23, 2 ¶ 21; Clarkson (2010) chs. genealogical tables, introduction ¶ 12, 2 ¶ 35; Broun (2004c) p. 117; Dumville (1999) p. 110; Ó Corráin (1998a) § 38; Ó Corráin (1998b) p. 331; Woolf (1998) pp. 159–160; Williams; Smyth; Kirby (1991) p. 134; Macquarrie (1990) p. 7; Anderson, AO (1922) pp. clvii–clviii; Phillimore (1888) pp. 172–173; Skene (1867) p. 15. Rhun is Arthgal's only known son.Bartrum (2009) p. 29.

In about 849, the ninth- to twelfth-century Chronicle of the Kings of Alba reports that Britons burned Dunblane, an ecclesiastical centre seated on the southern Pictish border.Evans (2015) p. 150; Clarkson (2010) ch. 8 ¶ 19; Downham (2007) p. 162; Woolf (2007) pp. 93–95; Davidson (2002) p. 126, 126 n. 75; Macquarrie (1998) p. 12; Hudson, BT (1998) pp. 148, 153; Anderson, AO (1922) p. 288; Skene (1867) p. 8. This attack took place during the reign of Cináed mac Ailpín, King of the Picts,Evans (2015) p. 150; Clarkson (2012a) ch. 8 ¶ 19; Clarkson (2010) ch. 8 ¶ 19; Downham (2007) p. 162; Woolf (2007) p. 101; Anderson, MO (2004); Macquarrie (1998) p. 12 n. 3. and may have been overseen by either ArthgalMacquarrie (1998) p. 12; Hudson, BT (1994) p. 52; Macquarrie (1990) p. 7. or his father, Dyfnwal ap Rhydderch.Macquarrie (1998) p. 12. The razing of Dunblane could be evidence that the Kingdom of Alt Clut was in the process of extending its authority at the expense of the Pictish regime. If so, the British kings would appear to have seized upon the chaos wrought by contemporaneous Viking attacks upon the Picts.Downham (2007) p. 162.

According to the Chronicle of the Kings of Alba, Rhun was married to a daughter of Cináed.Edmonds (2015) p. 60; Bartrum (2009) p. 286; Downham (2007) p. 163; Bhreathnach (2005) p. 269; Broun (2004c) p. 127; Hudson, BT (1996) p. 206; Hudson, BT (1998) pp. 149, 154; Ó Corráin (1998a) § 38; Ó Corráin (1998b) p. 331; Hudson, BT (1994) pp. 52, 55, 164 tab. 2a, 173 genealogy 6, 174 n. 3; Anderson, AO (1922) p. 363; Skene (1867) p. 9. This alliance may have been contracted between the Britons and Picts as a way of repairing international relations following the attack on Dunblane in 849.Clarkson (2012a) ch. 8 ¶ 19; Clarkson (2012b) ch. 11 ¶ 38. Rhun is the last listed king in the Harleian pedigree.Guy (2016) pp. 22–23; Clarkson (2014) chs. genealogical tables, 1 ¶ 23, 1 n. 56, 2 ¶¶ 21–22, 3 ¶ 19; Edmonds (2014) p. 201; Charles-Edwards (2013) p. 571; Clarkson (2010) chs. genealogical tables, introduction ¶ 12, 2 ¶ 35–36, 4 ¶ 44, 8 ¶ 23, 9 ¶ 4; Bartrum (2009) p. 642; Woolf (2007) p. 28; Charles-Edwards (2006) p. 324 n. 1; Broun (2004c) p. 117; Ó Corráin (1998a) § 38; Ó Corráin (1998b) p. 331; Dumville (1999) p. 110; Woolf (1998) pp. 159–160, 160–161 n. 61; Williams; Smyth; Kirby (1991) p. 134; Hudson, BT (1994) p. 72; Macquarrie (1990) p. 7; Macquarrie (1986) p. 21; Anderson, AO (1922) pp. clvii–clviii; Phillimore (1888) pp. 172–173; Skene (1867) p. 15. This could indicate that the genealogy was originally compiled during his floruitGuy (2016) pp. 22–23; Clarkson (2010) ch. 8 ¶ 23.—perhaps at the time of his marriage to his Alpínid wife, or upon the outset of his reign as king.Clarkson (2010) ch. 8 ¶ 23. According to the Chronicle of the Kings of Alba, a product of the marriage was a son named Eochaid.Bartrum (2009) pp. 286, 642; Hudson, BT (2002) p. 48; Hudson, BT (1998) pp. 149, 154; Anderson, AO (1922) p. 363; Skene (1867) p. 9. The twelfth-century Prophecy of Berchán describes Eochaid as "the son of the woman from Dún Guaire".Clarkson (2014) ch. 3 ¶ 22; Macquarrie (1998) p. 13; Hudson, BT (1996) pp. 44 § 135, 85 § 135, 206; Macquarrie (1990) p. 7; Anderson, AO (1930) p. 41 § 133; Anderson, AO (1922) p. 366; Skene (1867) p. 87. The fact that ninth-century Historia Brittonum identifies Bamburgh as Din Guoaroy could indicate that Dún Guaire too refers to Bamburgh.Clarkson (2014) ch. 3 ¶ 22; Hudson, BT (1996) pp. 85 n. 85, 206–207; Hudson, BT (1994) p. 55; Giles (1847) p. 342. Another possibility is that Dún Guaire refers to one of two similarly-named sites in the Hebrides (on Mull and Islay),Clarkson (2014) ch. 3 ¶ 22. In any event, the association of Rhun's wife with the fort could be evidence that she had been previously married.Hudson, BT (1994) p. 55.

King of Alt Clut

In 870, during the reign of Rhun's father, the fortress of Alt Clut was captured and destroyed by the insular Scandinavian kings Amlaíb and Ímar, following a naval blockade of four months.Jorgensen (2017) 48, 48 n. 145; The Annals of Ulster (2017) § 870.6; McLeod, S (2015) pp. 3, 11; Edmonds (2014) p. 200; Hudson, B (2014) p. 203; Charles-Edwards (2013) p. 480; Downham (2013) p. 17; Walker (2013) ch. 1 ¶ 40; Fraser (2012) p. 71; Downham (2011) p. 192; Gigov (2011) p. 23; McLeod, SH (2011) pp. 123–124; Clarkson (2010) ch. 8 ¶ 20; Fragmentary Annals of Ireland (2010) § 388; Davies (2009) p. 73, 73 n. 35; Ó Corráin (2008) p. 430; Fragmentary Annals of Ireland (2008) § 388; The Annals of Ulster (2008) § 870.6; Downham (2007) pp. 66–67, 142, 240, 258; Woolf (2007) p. 109; Forte; Oram; Pedersen (2005) p. 88; Costambeys (2004); Hicks (2003) p. 34; Valante (1998–1999) p. 245; Driscoll, ST (1998a) p. 112; Macquarrie (1998) p. 12; Ó Corráin (1998a) § 38, 38 n. 141; Ó Corráin (1998b) p. 331, 331 n. 149; Crawford (1997) p. 50; Hudson, BT (1994) p. 50; Smyth (1989) p. 215; Holm (1986) p. 321; Brooks (1979) p. 6; McTurk (1976) p. 117 n. 173; Alcock (1975–1976) p. 106; Anderson, AO (1922) pp. 301–302; Beaven (1918) p. 337 n. 36. In the following year, the twelfth-century Chronicon Scotorum,Edmonds (2014) p. 200; Chronicon Scotorum (2012) § 871; Chronicon Scotorum (2010) § 871; Broun (2007) p. 80; Downham (2007) pp. 240, 259; Kelly; Maas (1999) p. 144; Anderson, AO (1922) p. 303 n. 1. the fifteenth- to sixteenth-century Annals of Ulster,Downham (2018) p. 49; The Annals of Ulster (2017) § 871.2; Wadden (2016) p. 176; McLeod, S (2015) pp. 3, 11; Edmonds (2014) p. 200; Hudson, B (2014) p. 204; Downham (2013) p. 17, 17 n. 38; Gigov (2011) p. 23; McLeod, SH (2011) pp. 123–124, 171–172 n. 339; Clarkson (2010) ch. 8 ¶ 20; Ó Corráin (2008) p. 430; Sheehan (2008) p. 289; The Annals of Ulster (2008) § 871.2; Broun (2007) p. 80; Downham (2007) pp. 22–23, 66–67, 142, 240, 259; Woolf (2007) p. 109; Costambeys (2004); Hicks (2003) p. 34; Hudson, BT (2002) p. 33; Sawyer (2001) p. 10; Kelly; Maas (1999) p. 144; Driscoll, ST (1998a) p. 112; Macquarrie (1998) p. 12; Ó Corráin (1998a) § 38; Ó Corráin (1998b) p. 331; Smyth (1989) p. 215; Holm (1986) p. 321, 321 n. 10; Pelteret (1980) p. 106, 106 n. 64; Ó Corráin (1979) p. 319; Alcock (1975–1976) p. 106; Anderson, AO (1922) pp. 302–303; Beaven (1918) p. 337 n. 36. and the eleventh-century Fragmentary Annals of Ireland reveal that Amlaíb and Ímar returned to Ireland with a fleet of two hundred ships, and a mass of captives composed of English, Britons, and Picts.Downham (2011) p. 192; Fragmentary Annals of Ireland (2010) § 393; Fragmentary Annals of Ireland (2008) § 393; Downham (2007) pp. 142, 240, 259; Forte; Oram; Pedersen (2005) p. 88; Kelly; Maas (1999) p. 144; Macquarrie (1998) p. 12; Ó Corráin (1998a) § 38 n. 142; Ó Corráin (1998b) p. 331 n. 150; Hudson, BT (1994) p. 51; Ó Murchadha (1992–1993) p. 59; Anderson, AO (1922) p. 303 n. 1. The exportation of these people to Ireland is also attested by Annales Xantenses, a ninth-century German source.Sheehan (2008) p. 294 n. 64; Holm (1986) p. 321, 321 n. 11; De Simon (1909) p. 30 § 871. The captives could have been meant for ransom,Forte; Oram; Pedersen (2005) p. 88. or may have been intended for the Dublin slave market.Clarkson (2014) ch. 3 ¶ 9; McLeod, SH (2011) p. 124; Sheehan (2008) p. 289; Downham (2007) p. 23; Forte; Oram; Pedersen (2005) p. 88; Crawford (1997) pp. 50–51; Holm (1986) p. 321. It is possible that Arthgal and his family were amongst those imprisoned.Clarkson (2014) ch. 3 ¶ 9; Clarkson (2012a) ch. 8 ¶ 21; Clarkson (2012b) ch. 11 ¶ 45; Oram (2011) ch. 2; Clarkson (2010) ch. 8 ¶¶ 20–21; Macquarrie (1998) p. 12; Macquarrie (1990) p. 7.