William Percival Jervis was a nationally known master potter. He rented a studio in the Rose Valley Guild Hall. He created many highly praised pieces marked with the Rose Valley seal. He produced The Encyclopedia of Ceramics and wrote Rough Notes on Pottery, A Book of Pottery Marks and English Potters and American History.

He left his pottery shop in Rose Valley in 1904.

Sources: 
Exhibition of Rose Valley Art and Handicrafts 2001
History of Rose Valley, vol.1
A Poor Sort of Heaven, A Good Sort of Earth: The Rose Valley Arts & Crafts Experiment (Exhibition Catalogue, Brandywine River Museum, 1983.)