The Convocation of Oblivion was a gathering of Time Lords presided over by the Zero Nun.
They brought the Fourth Doctor before them to explain his recent actions, under threat of erasure by the Sword of Never. He told them of his encounter with Scratchman, demonstrating the Time Lords' failure to face their fears as he told it. Though outraged at his conclusions, the Convocation let him walk free. (PROSE: Scratchman)