The Treaty of Ka'Tann was a peace treaty negotiated by Ambassador V'Lar during the late 21st or early 22nd century.

While T'Pol was in her early schooling on Vulcan, she traveled to Vulcana Regar to see V'Lar during her negotiation for the Treaty of Ka'Tann.

At one of the recesses, during the second Ka'Tann Conference, T'Pol approached V'Lar to question the ambassador about her negotiating tactics, which V'Lar later recalled as being "quite presumptuous coming from one so young."

V'Lar later noted that T'Pol's bluntness made the ambassador reconsider some of her positions in negotiating the treaty. (ENT: "Fallen Hero")