Webster seems to have participated in many dramatic collaborations, but his undisputed work consists of only three plays: The White Devil (1612), The Duchess of Malfi (1614), and The Devil's Law Case (1623). His two great tragedies, The White Devil and The Duchess of Malfi, are darkly poetic and brooding, especially in their sardonic villain-spokesmen, Flamineo and Bosola. As critic Robert Dent has shown, Webster plundered other authors for his laborious, jewel-like, sententious, and epigrammatic style, but the overall effect is one of a soaring and passionate poetry. Webster employs the full gamut of violent and sensational effects, especially in The Duchess of Malfi, to render a physical sense of horror. His plots are drawn from the political and amorous intrigues of Renaissance Italy.