The Bloodsworn Vale lies within the Mindspin Mountains on the border between Varisia and Nirmathas. It was the site of a large, months-long battle in 4396 AR between the Chelish army led by Field Marshall Korvosa and the defending Shoanti natives. It is generally held to have been one of the bloodiest battles of the Everwar, which is what the Chelish war of expansion was eventually called. The fields of roses that lie in the valley mark the graves of the many Shoanti and Chelaxian soldiers that died fighting over this land.
Near the end of the Age of Enthronement, the vale was also a major trade route between Cheliax and its northern holdings in Varisia. The trail, however, fell into disuse during the Chelish Civil War and was eventually overtaken by the encroaching wilderness. In 4707 AR, King Arabasti of Korvosa called upon Sir Gyrad Tolgrith to reclaim the vale and reopen the trade routes, resulting in the founding of Fort Thorn within the vale to aid in this effort.