Sadly not whole works, but there are surviving fragments. I had forgetten how hard they are track down... Here's probably your best bet: https://archive.org/det

Sadly not whole works, but there are surviving fragments. I had forgetten how hard they are track down... Here's probably your best bet: https://archive.org/details/oldersophists0000unse/page/n6/mode/1up https://archive.org/details/oldersophists0000unse/page/n6/mo... (there's another book too, in a strange binding (thin and large) that I liked a bit better on him, but my copy is in a storage unit due to its strange size, I'll update if I can recall its name or translator) Really, I threw him in there both because relativism has become popular in recent centuries (and really hasn't been for most of the history of philosophy), and because Plato/Socrates's idea of the Forms sounds absolutely bonkers unless it's understood as a response to/way to avoid the conclusions of Protagoras and other sophists in his school.