The land one managed (4)
I believe the answer is:
iran
'the land' is the definition.
(Iran is an example)
'one managed' is the wordplay.
'one' becomes 'i' (Roman numeral).
'managed' becomes 'ran' (I've seen this before).
'i'+'ran'='IRAN'
(Other definitions for iran that I've seen before include "Country lying to south of Caspian sea" , "Former Persia" , "Persia today" , "Modern name for Persia" , "It was known as Persia until 1935" .)