Besides following the virtues and being a warrior, to be accepted into the order, one has to obtain a magical shield with the coat of arms of the order on it. Following the initiation, one is measured on their deeds.
After first appearing in Ultima IV, the order had changed only very little over time and always stood for its ideals.
After the destruction of Serpent's Hold during the Great Cataclysm, the remnants of the order left for the Valorian Isles, and helped on the reconstruction of Jhelom, naming this new city Valoria. As a result the Order of the Silver Serpent was disbanded, replaced by the newly born Knights of Valoria.