Filed from 2 published puzzles

CCCLI

Set to 2 different clues across 2 published puzzles, most often “Last full year of St. Julius I's papacy” — The New York Times, Saturday, 27 March 2010.

5 letters

Every clue on record, most used first

Last full year of St. Julius I's papacyonce
The New York Times — Saturday, 27 March 2010
Mid fourth-century yearonce
The New York Times — Wednesday, 21 December 2005