While their were many political groups, most of which served to undermine Roman rule of Israel, there were four main religious orders of the Jews in Jerusalem at the time of Christ. Many Christians read of the Pharisees, Sadducees, Essenes, and Zealots, but really do not know what the purpose of each was.
The Pharisees were perhaps the most influential and vocal of the groups in Jerusulam 2000 years ago. The first historical mention of them is by the Roman historian Flavius Joseph who wrote of the various religious groups about 145 B.C. They may have developed from the Assideans (the Pious) who rebelled against the rule of Antiochus IV (and the Hellenistic Greek culture) in the Maccabean revolt of about 165 B.C. The name Pharisee actually translates to Separatists or Those Who Live Separate, and they were often known as Chasidim, which means Loyal to God, or Loved of God. They believed in the Torah and the Oral Traditions of the Hebrew ideas of the constant revelations of God. They believed in the Free Will of man and the Sovereignty of God. They believed there was a "future for the dead," the immortality of the soul, and in reward and punishment for the rightious and the evil. They beleived in human equality (at least for Jewish folks), and their teaching was more about ethics (right and wrong), than theology (worship). Most Christian writings and doctrine make it out that the Pharisees were self-righteous hypocrites, who believed in the letter of the law, but not the spirit. In fact Jesus often rebuked them for these behaviors.
However some historians think Jesus may have been a Pharisee in that much of his teachings seem to come from basic Pharisee beliefs. In fact the way Jesus would debate the Pharisees is seen as a sign of inclusion amongst them, rather than an outsider. The Pharisees believed in the Oral Torah (Talmud. The ever-revealing truth of God) and believed that debates were ways to understand it. The ideas of resurrection and life everlasting, forgiveness for everyone, and equality were all ideas of the Pharisees and are found in the teachings of Jesus.
The Sadducees became the Levites or High Priests of the Temple after Antiochus IVs Syrians desecrated the Temple about 175 B.C. They replaced the previous High Priests and swore to protect the Temple from any future desecrations. They set themselves up as the High Priests and even rulers of Jerusalem after that time and would rule until the final Roman destruction of the city in 70 A.D. The Sadducees denied the Talmud (Oral revelations of God), and believed in the strict interpretation of the Law of Moses as found in the Torah. They believed in the total purity of the Priestly class and attributed everything in life to man's free will. They did not believe in resurrection or in eternal life. They did not believe in any spiritual world (demons, Angels, and Devil). Jesus apparently was rebuking the Sadducees when he said in Matthew 22: 31, "But about the resurrection of the dead- have you not read what God said to you, 'I am the God of Abraham, the God of Isaac, and the God of Jacob? He is not the God of the dead but of the living." The Sadducees were opposed in many ways by the Pharisees, especially on ideas of purity, the Talmud, resurrection, forgiveness, and eternal life.
The Essenes may have started out as the Pharisees, but eventually separated from them, though there is some evidence that they may have actually descended from the original Levites of the Temple that were deposed by the Syrians under Antiochus IV. They were a group of very strict and zealous Jews who fought with the Maccbeans in the revolt against the Syrians. They believed in strict observance of the purity laws of the Torah and were noted for their ideas of communal property (very similar to the early Christians in the Book of Acts). They believed in mutual responsibility for each other and for society as a whole. they believed in daily worship and study of the scriptures as found in the Torah. They often avoided marriage, though it was not a condemned practice. They believed everything that happened was due to fate as God had predestined everything and did not believe in the ideas of free will, though they cherished personal freedoms and stood against the practice of slavery. They beleived in the afterlife, resurrection, and in purification rituals, especially with water (some say John the Baptist was an Essene). Many Essenes believed they were the last of the Generations of Man and believed that a Messiah was soon to come and save the Chosen People. Many believe the Dead Sea Scrolls were the Essene Library that was hidden and preserved when the Romans made their final push to rid Israel of the Zealots and other Jews. They believed in forgiveness and non-violence, and some historians believe Jesus may have learned in this tradition. The Essenes were definately outsiders in the society of Jerusalem 2000 years ago.
Finally there were the Zealots. These were nationalistic Jews who would go to any lengths to rid their land of Roman rule. The Romans considered them to be terrorists and instituted crucifixian as a punishment for those zealots who attacked, murdered, or committed acts of terrorism (sedition) agains the Romans. In fact this is what the Jewish leaders of the Temple accused Jesus of doing when they brought him before Pilate. They said that his followers called him King of the Jews and the Messiah who would drive the Romans out. The punishment for sedition against Rome was crucifixtion. Most Zealots were looking for a Savior who would bring Israel Salvation, were opposed to the use of the Greek language, and were very loyal to Jewish traiditions.
It was into this polical and religious mix that Jesus came, taught, suffered, died, and was resurrected so that everyone could have forgiveness and a personal relationship with God. He says as much when Pilate asks "you are a king then?" Jesus answers, "You are right in saying I am a king. in fact, for this reason I was born, and for this I came into the world, to testify to the truth. Everyone on the side of truth listens to me."
Truth, Love, Peace