The libretto has been praised by several biographers and historians. One said that "The dialogue contains many an authentic Gilbertian touch." Another found it "a gay, sparkling libretto". Sidney Dark and Rowland Gray wrote that "the book of "Thespis" is genuine Gilbert, the Gilbert whom nowadays all the world loves... "Thespis" once more emphasizes the fact that Gilbert's artistry was hardly affected with the passing of the years. Many of its songs might well have appeared in the later operas." They point out Mercury's "I'm the celestial drudge", which anticipates Giuseppe's "Rising early in the morning" in "The Gondoliers", and find the "real brand of Gilbertian topsy-turvydom" in the song about the former head of a railway company, "I once knew a chap who discharged a function". Isaac Goldberg thought that ""Thespis" looks forward far more often than it glances backward: It forecasts the characteristic methods, and now and then a character, of the later series. Its dialogue is comical, and, if anything, somewhat above the heads of the Gaiety audiences of 1871."