Persian king (6)
'persian king' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for xerxes that I've seen before include "One old king" , "King of Persia, 486-465 BC" , "------I, son of Darius I, attempted invader of Greece, 480-79 BC" , "King of Persia, son of Darius" , "ruler after Darius" .)
'persian king' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for shah that I've seen before include "Former Iranian ruler" , "Persian king" , "King of Persia" , "Former ruler of Persia" , "Title of deposed Iranian leader" .)