Monty Python And The Holy Grail producer Mark Forstater is suing the British comedy troupe over profits he says he’s owed from the spin-off Broadway musical Spamalot. Three members of the troupe, Michael Palin, Eric Idle and Terry Jones were in a London court today for opening arguments in the case Reuters reports. Forstater says that under a 1974 agreement with the Pythons he is entitled to one-seventh of profits derived from Holy Grail and any merchandise or spin-offs. Forstater’s lawyer Tom Weisselberg says his client had been receiving his seventh of the profits until 2005, when the Pythons had unilaterally reduced his share to one-fourteenth. Forstater says he believes he’s owed about $400,000. Palin, Idle and Jones are expected to testify in the case next week. The trial is expected to last four to five days.