Ancient Roman's pet love (4)

I believe the answer is:

cato

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'ancient roman's' is the definition.
'cato' can be an answer for 'roman's' (I've seen this before). I'm unsure of the 'ancient' bit.

'pet love' is the wordplay.
'pet' becomes 'cat' (cats are often kept as pets).
'love' becomes 'o' (love means zero in tennis).
'cat'+'o'='CATO'

Can you help me to learn more?

(Other definitions for cato that I've seen before include "Senator" , "classical writer" , "Marcus Porcius - , Roman politician, censor" , "Roman statesman" , "Ancient Roman censor" .)

I've seen this clue in the Evening Standard.

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