Italian city about to welcome a ruler (7)
I believe the answer is:
emperor
'ruler' is the definition.
(I know that emperor is a type of monarch)
'italian city about to welcome a' is the wordplay.
'italian city' becomes 'Rome' (city in Italy).
'about' shows that the letters should be reversed in order.
'to welcome' indicates putting letters inside (inserted letters are welcomed in).
'a' becomes 'per' (eg 'one a day' means 'one per day').
'rome' written backwards gives 'emor'.
'emor' enclosing 'per' is 'EMPEROR'.
(Other definitions for emperor that I've seen before include "Ruler; butterfly" , "Ancient Roman ruler" , "Ruler - penguin - size of paper" , "Pre-Rome (anag.)" , "Beethoven's Piano Concerto No. 5 in E-flat major" .)