Legendary ship arrives finally in old city (5)
I believe the answer is:
argos
'old city' is the definition.
'Argos' can be an answer for 'city' (Argos is an example). I'm not sure about the 'old' bit.
'legendary ship arrives finally' is the wordplay.
'legendary ship' becomes 'argo' (I've seen this in another clue).
'finally' says to take the final letters.
The final letter of 'arrives' is 's'.
'argo'+'s'='ARGOS'
'in' is the link.
Can you help me to learn more?
(Another definition for argos that I've seen is " Ancient Greek city".)