DRAMATIS PERSONAE
VINCENTIO, the Duke
ANGELO, Deputy
ESCALUS, an ancient Lord
CLAUDIO, a young gentleman
LUCIO, a foppish young nobleman
Two gentlemen, friends to Lucio
PROVOST
In the first Act Claudio is imprisoned for having pre-marital sex with Juliet. Tough break. 
 He is usually played by someone young and fairly pretty – think a slightly duller, dumber Romeo. 
 Here’s Alex Hassell having a go: 

Measure for Measure Characters of the Play