Rural museum's don's written about twins of old (7,3,5)

I believe the answer is:

romulus and remus

I'm a little stuck... Click here to teach me more about this clue!

'twins of old' is the definition.
'romulus and remus' can be an answer for 'twins' (I've seen this before). I am unsure of the 'of old' bit.

'rural museum's don's written about' is the wordplay.
'written about' indicates an anagram (letters moved about before being rewritten).
'rural'+'museum'+'dons'='ruralmuseumdons'
'ruralmuseumdons' anagrammed gives 'ROMULUS AND REMUS'.

Can you help me to learn more?

(Other definitions for romulus and remus that I've seen before include "They emerged from the pack" , "urban developers" , "Twins" .)

I've seen this clue in The Everyman puzzle in The Observer.

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