Christopher Marlowe's masterpiece, Edward II, is the first major English History play/tragedy in the renaissance canon, predating and providing a model for Shakespeare's Richard II and other plays of the genre (for that connection, see Charles R. Forker's magisterial introduction in the Manchester U Revels Plays edition). It's also an important work in the lgbtq literary canon, as the love affair between Piers Gaveston and his king is the first open and unabashed representation of gay characters on the English stage, and the poetry of that love affair is marvellous. The play also features a villainous cadre of Machiavellian lords and churchmen who despise Gaveston for his lower class beginnings, his and Edward's wasting of the nation's treasury, and for Gaveston's sexuality.
As a film, the play is already known to many through Derek Jarman's 1992 experimental version of it, featuring good performances by an angry, spiteful Gaveston (Andrew Tiernan)and Queen Isabella (a young Tilda Swinton). Its chief feature is a peculiar cutting and pasting of text and plotline, interlarding the play with a song performed by Annie Lennox and modern gay rights demonstrations and police brutality.
That said, the 1969 BBC Edward II starring a very young and gorgeous Ian McKellen in a filmed stage performance of the play is a wonderful surprise, a delight in every way. McKellen is more passionate, spontaneous, and utterly possessed by his role than I have ever seen him; he has obviously learned his chops, but there's a sense that this performance is 90% "going on nerves" in the best sense. James Laurenson's Gaveston is more nuanced than Tiernan's, and the film itself is less polemic than Jarman's: it focuses much more closely on the depth of their love. The supporting cast is uniformly excellent, and one should not be put off by the fact that this is a film of stage performance; the work is so good that one quickly overlooks the difficulties of transition. Costumes bring one a humorous reminder of the colorful sixties, but they aren't too intrusive, and the film quality is very good, given the fact that this is a product of that decade.