The peace treaty concluded between Bajor and the Cardassian Union in 2371, negotiated chiefly by Vedek Bareil Antos, who died of his injuries before it was signed.
The Bajoran-Cardassian Treaty is completed in the Deep Space Nine episode Life Support. Vedek Bareil has spent months in secret talks with the Cardassian representative Legate Turrel on behalf of Kai Winn. Their transport suffers an accident on its approach to Deep Space 9 and Bareil is gravely hurt.
Winn admits that she cannot finish the talks without his advice. Julian Bashir keeps Bareil alive with an experimental drug and then with artificial implants that replace part of his brain, although he warns that each step takes away more of the man. The terms include a formal Cardassian apology and the return of Bajoran property taken during the occupation.
The treaty is agreed, and Winn receives the credit. Bashir refuses to replace the rest of Bareil's brain, and the vedek dies with Kira Nerys beside him. Relations cool again in 2373 when Cardassia joins the Dominion.