There's some evidence of Roman settlement in the Santa Eulària region and, during the Moorish period, its river valley was cleverly irrigated and intensively farmed (find out more at Can Planetes). The Puig de Missa church was built in the late 16th century, with houses cropping up around it during the 18th century.
But the town was still little more than an overgrown village until the 1930s, when American writer Elliot Paul spent an extended period here. He documented the outbreak of the Spanish Civil War on the island in his 1937 book Life and Death of a Spanish Town (a wonderful read). During the 1960s and 1970s, Santa Eulària became something of a hangout for a British thespian set, centred on the then-popular, now-defunct bar Sandy's. Terry-Thomas and Denholm Elliott bought homes in the area, and Laurence Olivier, Elizabeth Taylor and John Mills holidayed in the town.
Today's Santa Eulària is a curious mix of summer resort (complete with British pubs) and a regular Spanish town with a touch of historical charm.