There is a similar effect in The Spanish Tragedy (c. 1591) by Marlowe‘s friend Thomas Kyd, an early revenge tragedy in which the hero seeks justice for the loss of his son but, in an unjust world, can achieve it only by taking the law into his own hands. Kyd‘s use of Senecan conventions (notably a ghost impatient for revenge) in a Christian setting expresses a genuine conflict of values, making the hero‘s success at once triumphant and horrifying. Doctor Faustus