Sigtrygg Silkbeard

He has a prominent role in the 12th-century Irish medieval text Cogadh Gaedhil re Gallaibh and the 13th-century Icelandic Njal's Saga, as the main Norse leader at the Battle of Clontarf (1014).

An incident involving the ransom of one of Sigtrygg's sons, late in his reign, in which "seven score British horse" were mentioned in the list of demands,[7] suggests that Dublin was one of the main ports for importing horses into 11th-century Ireland; it is thought that Sigtrygg and his family may have been personally involved in animal husbandry.

[8] Sigtrygg may have succeeded his paternal half-brother Glúniairn as king of Dublin in 989,[4] but it is just as likely his rival Ivar of Waterford came to power in the city then.

[10] Benjamin Hudson claims this was because of the arrival of the future King of Norway, Olaf Tryggvason, who took up residence in Dublin for a few years after marrying Sigtrygg's sister Gytha.

[10] The presence of a powerful Viking leader in Dublin was a deterrent to Irish raids, and Tryggvason may have weakened Sigtrygg's foes by plundering them.

[11] Hudson argues that Tryggvason's return to Norway in 994 coincided with the temporary expulsion of Sigtrygg from Dublin by his rival Ivar of Waterford.

[12] In 998, Máel Sechnaill and the King of Munster, Brian Boru, forced Sigtrygg to recognise their lordship by giving hostages.

[12] Sigtrygg first allied with his maternal uncle, Máel Mórda mac Murchada, King of the Uí Fáeláin of north Leinster.

[12] Late in 999, the Leinstermen, historically hostile to domination by either the Uí Néill overkings or the king of Munster, allied themselves with the Norse of Dublin and revolted against Brian Boru.

[12] Brian's forces inflicted a crushing defeat on the united Leinster-Dublin army at the Battle of Glenmama, and followed the victory with an attack on the city of Dublin.

[16] Cenél Conaill, the last of the Northern Uí Néill Kingdoms, submitted in 1011, and Brian was formally recognised as High King throughout Ireland.

[16] A remembrance of Sigtrygg's reign during these years is preserved in the late medieval Icelandic Saga of Gunnlaug Serpent's Tongue.

[18] Only fragments survive of the verses in the Sigtryggsdrápa, a drápa composed by the skald Gunnlaug Illugason while visiting Sigtrygg's court.

[16] According to Njál's saga, Gormflaith "egged on her son Sigtrygg very much to kill King Brian",[6] sending him to win the support of Earl Sigurd of Orkney, and Bróðir and Óspak of Man at any price.

[28] As the modern Irish medievalist historian Donnchadh Ó Corráin notes, Sigtrygg "wisely kept within the city and lived to tell the tale".

[28] The Darraðarljóð, showing the persistence of paganism among the Vikings of Dublin, describes the Valkyries as following the "young king" Sigtrygg into battle.

[33] When Sigtrygg raided south in 1021, he was defeated at Delgany in County Wicklow[33] where the new King of Leinster, Augaire mac Dúnlainge, "made a dreadful slaughter of the foreigners" in the Kingdom of Breifne.

[34] In 1022, the Dublin fleet sailed north against the Ulaid, only to be destroyed in a naval battle against Niall mac Eochaid, after which the Norse crews and ships were taken prisoner.

[33] According to the American medievalist historian Benjamin Hudson, "matters went from bad to worse" for Sigtrygg after the death of Máel Sechnaill in 1022.

[35] The great Irish princes began to compete for the High Kingship, and the political situation in Ireland became chaotic as there was no clear choice for supremacy.

[35] These hostages brought no security, and Dublin was raided in 1026 by Niall mac Eocada of the Ulaid in revenge for the naval attack of 1022.

[8] The incident illustrates the importance of ransoming noble captives, as a means of political manipulation, increasing one's own revenues and exhausting the resources of one's foes.

[39][46] It is thus possible to attribute the origins of the establishment of territorial bishoprics in Ireland on the Roman model, one of the most important results of 11th-century Irish Church Reform, to Sigtrygg.

The cathedral, initially a wooden building, was rebuilt in stone in the 1180s following the arrival of the Anglo-Normans to Ireland, led by Richard de Clare, 2nd Earl of Pembroke.