Possible Clues:

• Legendary weapon's former quality spoken of
• Former measure of ammunition, say, for weapon
• Excellent burial arrangement for Arthur's sword
• Proclaimed former quality of sword
• Smart rogues and rascals take something for granted?
• Tennyson ''brand'' name
• The legendary sword of King Arthur
• The Sword in the Stone?
• 1981 film in which Helen Mirren plays a sorceress
• Noted weapon, a club Rex and I toyed with