Of medieval origin, this hermitage is dedicated to the cult of the holy Roman martyr taken as a lawyer against epidemics and contagion. The temple was rebuilt in 1745, under the direction of the masters Diogo Tavares de Ataíde, Manuel Aleixo and Jacinto Pacheco. Small in size, the temple adopts a simple plan of rectangular single nave, chancel and sacristy, in line with the “ground style”. It is mainly through the interior decoration of the temple that the Baroque expresses itself with greater exuberance, complementing and energizing the walls of the building. At the end of the campaign of reconstruction of the hermitage was executed the exuberant work of painting of its interior by Diogo de Mangino, a local painter of a certain notoriety. He was forced in 1759 to make the paintings of the chancel, including ten panels with the life of St. Sebastian, the fake marble of the walls and also the upholstery of two sculptures of tocheiros angels. This series of ten canvases on São Sebastião stands out, considered the most complete pictorial recreation of the life of the saint that exists in Portuguese art. Other local masters later completed the painting campaigns, extending to the temple body.