The Black Rocks are a set of rocks located in the Colovian Highlands near the city of Chorrol and the site of the Battle of Black Rocks which was a conflict between the Third Legion and the Second Aldmeri Dominion in the Tiber Wars.
Camoran Anaxemes established the Second Aldmeri Dominion with the Altmer in the Summerset Isles to take territories in Colovian West. When Tiber Septim took over as Emperor of Cyrodiil after Cuhlecain's assassination, he launched a campaign to take control of all the provinces in Tamriel to unite under a single empire. His army fought the Aldmeri Dominion throughout Colovia in places such as the Black Rocks. The Aldmeri Dominion brought the Third Legion into a trap in the Black Rocks which lead to the Aldmeri Victory as well as the formation of the Ruby Legion.[OOG 1]