Anselan was Warder to Barashelle. He was considerably older than her, and stubborn.
Barashelle bonded a Warder while she was still Accepted so, as punishment, she was forced to pass the Bond to another Aes Sedai and bond Anselan when she was raised to the shawl.
The story of Barashelle and Anselan is, however, told to most people as a love story in The Flame, the Blade and the Heart, with Barashelle and Anselan being portrayed as heroes and lovers. Birgitte reveals the truth of the situation to Elayne.