The most common and most likely answer to this crossword clue is the 7 letter word TACITUS
I've seen this crossword clue in The Times
T
A
C
I
T
U
S
More clues leading to the result TACITUS
- Historian understood by you and me
- Understood American historian
- Account penned by Greek disciple for Roman historian
- Old historian’s account embodied in biblical book
- Prominent Roman penning account?
- Old history master understood our group
- Historian’s account in NT book
- Historian understood American
- Historian of The Quiet American?
- Historian can be understood by you and me
Buddy explains!

The straight part
We know that "Historian" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case historian = tacitus.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.