A quest to Telos IV was embarked upon in 53 BBY by Jedi Masters Qui-Gon Jinn and Tahl, along with Jinn's apprentice Xanatos, and the Masterless Padawan Orykan Tamarik.
Yoda, along with several other members of the Jedi Council, including the Grand Master, had been concerned regarding Qui-Gon Jinn's apprentice, Xanatos, for some time. They therefore decided to evaluate him one last time before bestowing upon him the title of Jedi Knight. Xanatos, Jinn, Tahl, and Orykan Tamarik, two other Jedi, together undertook a mission to the planet of Telos IV.
Upon the Jedi's arrival, they discovered that Crion, Xanatos's father, had become a tyrannical ruler of the planet, abusing his authority as governor. Following the death of his sister, Nason, Xanatos succumbed to the temptation of his father's power and wealth, choosing to join him in ruling the planet. This decision plunged the planet into a civil war.
Jinn confronted Crion, inadvertently causing the governor's death while attempting to protect Tamarik. Witnessing his father's demise, Xanatos flew into a rage and seized a ring from Crion's finger, which was searing hot from the fire he had fallen into. He used it to brand his cheek, leaving a broken-circle scar. Vowing revenge, Xanatos then fled the scene.
Jinn went back to the Jedi Temple and took responsibility for Xanatos's failure, disavowing his success in training his first Padawan.