The name of the commune comes from the association of "plou", that is to say "parish" and Idult, great saint Welsh. Its territory abounds with mansions, noble houses, chapels ... In the borough, the town hall, formerly presbytery, manors and stone houses fully justify the obtaining of this label. A circuit decorated with explanatory panels allows to discover the different uses of these buildings. The interior of the Saint-Pierre church is one of the rare examples of Romanesque art in Brittany. In the village of Crénénan, the chapel of Notre-Dame is surrounded by astonishing constructions that are supposed to be beer cellars. At Locuon, once a truce in Ploërdut, the Notre-Dame de la Fosse chapel is built in an old Gallo-Roman quarry, the blocks of which were used for the construction of Vorgium (Carhaix). Closer to us, history retains that in the 19th century, the school included among its teachers a granddaughter of Napoleon. His father, Count Leon, was the son of the Emperor.