Brisingr

Eragon wonders how Saphira was able to keep this from him, even under oath. He almost immediately accepts it to be true. Brom gave Saphira a gift to pass on to Eragon, a memory of Brom speaking to Eragon. Before Saphira shows it to him, Oromis asks if he can share some of Brom’s story. Brom and Morzan were apprenticed to Oromis, and they loved each other like brothers until Morzan betrayed them all to join with Galbatorix and kill Brom’s dragon, the original Saphira. For decades, Brom was filled with hate; when the Varden first heard of the Black Hand, they sent Brom to spy on her as a gardener in Morzan’s estate near the foothills of the Spine and Leona Lake (where it still stands today). They believe the love between Brom and the Black Hand was real, and not premeditated to upset Morzan. She freely switched sides to spy for the Varden and supply them with information about Morzan. In fact, Morzan trusted her to go on missions for him, where she met with Brom instead.

Brom only left his position as gardener after three years, when Jeod heard about a secret way into the castle at Urû’baen; of the three dragon eggs, Hefring was only able to secure one (Eragon’s Saphira) and he betrayed them by running off with the egg.