Grueby refers to potteries and architectural pieces made by William Henry Grueby (1867-1925). He developed his own glazes and created matte-finish potteries, unlike the glossy glazes prevalent at the time. Grueby started many pottery companies individually and jointly, with his name such as Atwood & Grueby, Grueby Faience Company, Grueby Pottery Company and Grueby Faience and Tile Company at various times in his life time. The company name was often used as the mark so it helps date a piece. The matte green glazed pieces are the most sought after today.