A war hero from Ephebe, and the Disc's answer to Odysseus. He led Ephebe in the battle at Tsort. It is generally believed that the Ephebians made a giant wooden horse that the army hid in, which was pulled into the city by the Tsortians; at night the Ephebians burst out of it and rescued the beautiful Elenor. In fact, the horse only contained Rincewind and Eric, and Lavaeolus and his men sneaked around to 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 couldn't take their brains out of their underwear. In addition, he didn't like sailing, because of all the yelling involved. Unfortunately, after ten years besieging Tsort, he spent the next ten years trying to get home.
It is possible that Lavaeolus (Washer/Rinser of Winds) is a distant ancestor of Rincewind. If this is indeed the case, 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 the hapless Wizzard, who has later proved in the Science of Discworld books to come up with a non-killing battle strategy, and convince the other wizards to take part.
Lavaeolus' Roundworld counterpart is Ulysses, also known as Odysseus, who feigned madness to be kept out of the war, and took ten years to get back after being forced to go. These ten years were full of tribulations, to say the least. So were Lavaeolus', which is 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.