The legend of King Arthur and the Knights of the Round Table receives its most impressive screen treatment in "Excalibur", from visionary moviemaker John Boorman ("Deliverance", "The Emerald Forest"). All the elements of Sir Thomas Malory's classic "Le Morte D'Arthur" ("The Death of Arthur") are here: Arthur (Nigel Terry) removing the sword Excalibur from the stone; the Round Table's noble birth and tragic decline; the heroic attempts to recover the Holy Grail; and the shifting balance of power between wily wizard Merlin (Nicol Williamson) and evil sorceress Morgana (Helen Mirren). With Patrick Stewart, Gabriel Byrne and Liam Neeson in notable early screen roles.