According to
Alban Butler, Plechelm was an English Saxon born in southern Scotland. Richard Stanton places him in the north of England. After being ordained, he made a pilgrimage to Rome with two fellow monks, Saints
Wiro and Otger. Having been consecrated a bishop, perhaps by
Pope Sergius I, he returned home with some holy relics. He then started with Wiro and the deacon Otger on a mission to Gaul. They were well received by
Pepin of Herstal, who gave the missionaries
St. Peter's Mount (also known as Sint Odiliënberg). They built a monastery there which was important in the
Christianisation of the Netherlands. Many missions were sent from there to the provinces between the Rhine and the Meuse. According to
John O'Hanlon, it is said that Plechelm and Wiro were present at the Synod of Utrecht in 697. Plechelm died in
Sint Odiliënberg at the age of 100 years. ==Veneration==