To mark the morn's news of Rowan Williams' retirement as archbishop of Canterbury, here's fullvideo of perhaps the key ecumenical moment of the Anglican primate's decade-long tenure: the joint Evensong which he led with B16 in Westminster Abbey during the Pope's 2010 State Visit to Britain -- a moment widely considered in the Vatican as the high-point of the pontiff's historic pilgrimage, liturgically and otherwise.-30-