Who is William Hogarth from Understanding Comics and what is their importance?

Hogarth's Hogarth's landmark six-plate picture-story from 1731, entitled "A Harlot's Progress," is hailed by McCloud as a sign of sophistication in the growth of comics. McCloud is especially interested in the fact that Hogarth is not considered a comics artist, yet his stories are first exhibited as a series of paintings and later sold as a portfolio of engravings that are all designed to be viewed side-by-side, in sequence. This unusual feature allows McCloud to fit this work of art into his definition of comics as sequential art.