Earliest uses of the term Pharisee: Paul’s letters (50′s CE), Mark’s gospel (probably 60′s CE), Josephus’ works (80-90 CE).
Earliest references to Pharisees: Dead Sea Scrolls perhaps refer to Pharisees with terms like “seekers of smooth things.”
Earliest historical appearance of Pharisees: reign of Jonathan (161-143 BCE).
Earliest event specifically mentioned to involve them: They asked Hyrcanus to step down as high priest, leading him to abandon the Pharisee party and become a Sadducee (c. 135-104 BCE, Josephus Antiq. 13.288-298).
Earliest literature by a Pharisee: many scholars believe the Psalms of Solomon (c. 60 BCE) are written by Pharisees.
Reference: Sanders, E.P. Judaism: Practice and Belief. Philadelphia: Trinity Press International, 1992.