Sadducees were a Jewish sect in Judea during the Second Temple period. This sect controlled the priesthood and was highly involved in political responsibilities, like controlling the Sanhedrin. They were also fond of Roman Hellenistic thinking. This way of thinking brought order and structure into the sect.
Hellenistic thinking also brought up theological conversations and a new way of teaching The Torah. This separated the Sadducees from the Pharisees because they denied the oral traditional teaching of the time and relied on the Pentateuch (the first five books of Moses) for teaching. They would also separate themselves from the beliefs of the Pharisees by denying the idea of predestination and the immortality of the soul.