CLX

Set to 4 different clues across 4 published puzzles, most often “160, to Caesar” — The New York Times, Wednesday, 20 May 2009.

3 letters

Every clue on record, most used first

160, to Caesaronce
The New York Times — Wednesday, 20 May 2009
160, onceonce
The New York Times — Wednesday, 4 July 2007
XX times VIIIonce
The New York Times — Tuesday, 1 May 2001
Year before Marcus Aurelius became emperoronce
The New York Times — Sunday, 5 December 1999