Samson Agonistes is a closet play, i.e. a play not meant for performance. It was first printed in 1671, together with Milton's Paradise Regained. The play is a tragedy. Its protagonist is Samson, a figure well-known to Christians from Old Testament history (and from later commentaries, sermons, and imaginative literature, including political texts from England's revolutionary period). The second word in the title is an epithet in Greek, agonistês, meaning a man who is a contender in athletic events such as wrestling competitions, or who—in one seventeenth-century definition—“plays the champion”.
The text of Samson Agonistes is preceded by Milton's prefatory prose “ epistle” (…
Moschovakis, Nicholas. "Samson Agonistes". The Literary Encyclopedia. First published 26 September 2006
[https://www.litencyc.com/php/sworks.php?rec=true&UID=2301, accessed 21 March 2018.]