Complex sentence: In 1870 the manufacture of "Art pottery" was begun at Lambeth, and in 1877 works were opened at Burslem, where almost every variety of china and porcelain, as well as artistic earthenware, has been produced.
Split into simpler sentences: In 1870 the manufacture of "Art pottery" was begun at Lambeth. In 1877 works were opened at Burslem, where almost every variety of china and porcelain, as well as artistic earthenware, has been produced.