Playgoers of the Southwark Theater in Philadelphia on 24 April 1767 were entertained by a production of a new play, The Prince of Parthia, the first play written by a native-born American to receive a professional production. Thomas Godfrey, its author, was not there to receive the congratulations of his friends and neighbors, for he had died nearly four years before, but on the basis of a handful of poems and his play, a surprisingly effective work from a young, provincial author, he has secured his claim to remembrance. Godfrey was born in Philadelphia, the son of Thomas Godfrey, Sr., who had invented the navigator's quadrant and was a member of Benjamin Franklin's Junto. Godfrey senior was a glazier, self-taught and with a propensity for mathematics; legend has it that he discovered the principle of the quadrant while replacing a pane of glass for James Logan and noticing the sun's...