Mythological king, one being carried like a baby? (5)
I believe the answer is:
priam
'mythological king' is the definition.
'one being carried like a baby?' is the wordplay.
'one' becomes 'i' (Roman numeral).
'being carried' means one lot of letters goes inside another (one word carried by another word).
'like a baby?' becomes 'pram' (I can't justify this - if you can you should believe this answer much more).
'i' placed within 'pram' is 'PRIAM'.
(Other definitions for priam that I've seen before include "The last king of Troy, in Greek mythology" , "Ruler of Troy" , "Father of Paris in Troy" , "Old man of Paris" , "Old king" .)