Towards the end of Ruysbroeck's life, in 1378, he was visited by the fervid lay-preacher Gerhard Groot (1340-1384), who was so impressed by the life of the community at Groenendal that he conceived the idea of founding a Christian brotherhood, bound by no monastic vows, but living together in simplicity and piety with all things in common, after the apostolic pattern.
The founder was William O'Bryan (afterwards Bryant), a Methodist lay preacher of Luxillian, Cornwall.
In 1650 John Knowles was an Arian lay-preacher at Chester.
Woodman then returned to his native Sussex where he became an itinerant lay preacher.
Tell me, just explain " lay preacher " .