One hundred years ago, his mate's brother, who was a dragon rider, was killed by Kialandí in Ilirea. Naudra received the sword Támerlein from her dying brother. He gave it to her so she may make it out alive. She left with another dragon rider and took it with her to Ellesméra. She died soon after, on account of her injuries, and left Tamerlein with Lord Fiolr. It has since remained the greatest treasure of House Valtharos.
When Eragon required a Rider's sword to replace Zar'roc, he asked Fiolr for permission to use Támerlein. Fiolr explained its history and said he was more attached to that sword than his own soul. He allowed Eragon to use it, only under the conditions that the sword remained the property of the house of Valtharos and he would have to return if Lord Fiolr or his heirs asked for it. Eragon tried out the sword and found that it was made for a different fighting style then he used and that the hilt was too large for his hand. For these reasons, Eragon decided not to use the sword. Fiolr was relieved that he wouldn't have to give up his greatest treasure.