Caill Tomair
Caill Tomair, or Þorsviðr in Old Norse, was a Sacred trees and groves in [Germanic paganism and mythology|sacred grove] dedicated to the North Germanic god Thor. Though its exact location is uncertain, it is believed to have been located near the Norse-Gaelic city of Dublin. According to Cogadh Gáedhel re Gallaib, a 12th-century Munster chronicle that glorifies Brian Boru's campaigns against Norse and Gaelic rivals, The grove was destroyed by forces led by Brian Boru early in the year 1000 AD.
According to scholar Poul Holm, the grove was likely targeted due to its role among the local population:
According to the Cogadh Gáedhel re Gallaib, when Brian Boru captured Dublin in the year 1000, his forces symbolically destroyed Caill Tomair by cutting it down and burning it. This act represented the subjugation of the Norse and the dismantling of their religious and cultural symbols. The destruction was so impactful that it was still being remembered 14 years later, during the Battle of Clontarf in 1014, when the chaos of battle was likened to the felling and burning of the grove.