Peter Chamberlen M.D. (1601–1683), known as Peter the Third, was an English physician. The obstetrical forceps as invention has been credited to the Chamberlen family: the earliest evidence of what was a family trade secret points to his having it in 1630. He continued the family tradition of trying to bring the profession of midwifery under their control. His writings blend ideas associated with the Fifth Monarchists and Levellers with social schemes of his own with a utopian flavour.