Lavaeolus was a war hero from Ephebe, and the Disc's equivalent to Ulysses, also known as Odysseus and the hero of Homer's book of the same name. Like Lavaeolus, Ulysses feigned madness to be kept out of the war and took ten years to get back home after being forced to go - the subject of Homer's Odyssey. Lavaeolus led Ephebe in the battle at Tsort. The legend held that the Ephebians made a giant wooden horse that the army hid in, which was pulled into the city by the Tsortians and at night the Ephebians burst out of it to rescue the beautiful Elenor. In fact, the horse only contained Rincewind and Eric, while Lavaeolus and his men snuck in the back.
Lavaeolus wore a rusty breastplate and a helmet with an unkempt plume. He didn't really like violence and always looked for alternatives to it. He also despised the other officers, because they liked violence and thought with the more basic parts of the male anatomy instead of their brains. In addition, he didn't like sailing, because of all the yelling involved, another problem given that after ten years spent besieging Tsort, he took anothert ten years to get home. This would explain why he was so unimpressed with Rincewind, his descendant when they met in Hell, after having been told that he'll get home all right.
Lavaeolus' name is intended to be a play on Rincewind as it appears to be a loose Latin translation of Washer/Rinser of Winds (Lava is wash). He is likely an ancient ancestor of Rincewind which suggests that all of the competency except for language, active pacifism, self-preservation and talent with improvisation got bred out of the bloodline by the time it reached his hapless present day descendant.