### Clue: Quiet historian losing footing on edges of ruin (8)
### Answer: TACITURN 
 ### Explanation: Definition: Quiet 
 "Tacitus"(historian of the Roman Empire) **minus its last letter**(losing footing, in a down clue) **placed above**(on, in a down clue) **the 1st and last letters of**(edges of) "ruin".