Brother Methuselah was the oldest Abbey mouse in the whole of Redwall and he was the wisest and cleverest. Abbot Mortimer often asked his advice. Methuselah was the Abbey's chronicler and recorder. He was instrumental in the Wars of the Late Rose, and he aided Matthias in finding the Shield of Martin the Warrior, and the shield-belt, and the scabbard of Martin's Sword.
Brother Methuselah was the one who discerned that Cluny was coming to Redwall. Abbot Mortimer had assured them that Cluny was real, and Brother Methuselah gave the final proof. Methuselah was also shocked that the mice didn't believe Mortimer. He was one of the ones who was present when Cluny threatened Mortimer and said that he would take Redwall as his.
Methuselah had the gift of tongues, and could understand any creature. Methuselah was also one of the only Redwall mice in that time, and maybe centuries, to visit the famous Tomb of Martin the Warrior, which was considered mythical. Methuselah proved that Martin was reincarnated in Matthias, because his code name, "I am that is," was "Matthias," mixed up.
Methuselah and Matthias both visited the famed Tomb, and Methuselah was noted for being allowed in by Martin himself despite the fact that Martin's riddle said only his reincarnation could enter.
Methuselah was devastated when the Shadow had stolen Martin's tapestry, and vowed for it back. When Jess Squirrel and Basil stole the tapestry back, Methuselah was delightedly stitching it back together. However, Chickenhound, the traitorous healer fox that Cluny had attempted to kill, had escaped from the infirmary, and he betrayed the Redwallers' hospitality by stealing. Chickenhound ran from Friar Hugo, and Brother Methuselah, stitching the tapestry, tried to stop him, but Chickenhound called Brother Methuselah a stupid fool and smashed his treasure bag onto the old mouse's skull, killing him.
A bell was named after Methuselah in his honour.