Roman emperor's wife initially letting one through (5)

I believe the answer is:

livia

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'roman emperor's wife' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.

'initially letting one through' is the wordplay.
'initially' says to take the initial letters.
'one' becomes 'i' (Roman numeral).
'through' becomes 'via' (via means going through).
The first letter of 'letting' is 'l'.
'l'+'i'+'via'='LIVIA'

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(Other definitions for livia that I've seen before include "Wife of Caesar Augustus" , "Anna ..... is the literary Liffey" , "James Joyce christened the Liffey 'Anna ....'" .)

I've seen this clue in The Times.

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