They had their villas and old ruined manors (6)
I believe the answer is:
romans
'they had their villas and old' is the definition.
The definition suggests an adverb but the answer is not.
'ruined manors' is the wordplay.
'ruined' indicates anagramming the letters.
'manors' with letters rearranged gives 'ROMANS'.
Can you help me to learn more?
(Other definitions for romans that I've seen before include "Empire builders" , "New Testament book" , "Countrymen of Mark Antony" , "Ancient Italians" , "Mark Antony's countrymen?" .)