a Northumbrian missionary of the 8th century, who with Wiro and Otger went to Rome on pilgrimage, was consecrated bishop there, and evangelized the area of the Meuse valley in the Netherlands. They built a church and monastery at Roermond through endowments given by Pepin of Herstal, who was closely associated with both Plechelm and Wiro. There is some uncertainty about these saints, in so far as they have often, but wrongly, been claimed to be Irish; it is also possible that they were consecrated not at Rome but by Willibrord. Plechelm died at Odilienberg and was buried there; later his relics were translated to Roermond. Feast: 16 July.
From The Oxford Dictionary of Saints in Oxford Reference.