The most common and most likely answer to this crossword clue is the 7 letter word LATERAN
I've seen this crossword clue in The Guardian
L
A
T
E
R
A
N
More clues leading to the result LATERAN
- More recent article identifying old Roman palace
- Palace council that’s dead organised
- Charged after having departed Roman site
- Palace in Italy stripped back, Pope finally managed
- Construction of largely new altar in cathedral church of Rome
- In the wee hours, managed site in Rome
- Roman palace in more recent article
Buddy explains!

The straight part
We know that "Roman site" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case roman site = lateran.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.