king vs Xerxes I

king and Xerxes I both are nouns.

Word	Noun	Adjective	Verb	Adverb
king	Yes	No	No	No
Xerxes I	Yes	No	No	No

king (noun)	Xerxes I (noun)
(chess) the weakest but the most important piece	king of Persia who led a vast army against Greece and won the battle of Thermopylae but was eventually defeated (518-465 BC)
one of the four playing cards in a deck bearing the picture of a king
a checker that has been moved to the opponent's first row where it is promoted to a piece that is free to move either forward or backward
a male sovereign; ruler of a kingdom
a very wealthy or powerful businessman
a male competitor who holds a preeminent position
the husband or widower of a queen
preeminence in a particular category or group or field