Jesus is the central figure of Christianity. For some believers, Jesus is the son of God and the Virgin Mary, who lived as a Galilean Jew, was crucified under Pontius Pilate, and rose from the dead. Even for many non-believers, Jesus is a source of wisdom. In addition to Christians, some non-Christians believe he worked healing and other miracles. Believers debate issues of the relationship between Jesus as God the Son and God the Father. They also debate aspects of Mary. Some believe they know details about the life of Jesus not recorded in the canonical Gospels. Debates sparked so much controversy in the early years that the emperor had to convene gatherings of Church leaders (ecumenical councils) to decide the course of Church policy.
About.com's Guide to Judaism explains the Jewish beliefs as regards Jesus. In her article Who Was Jesus? The Jewish View of Jesus, Ariela Pelaia writes:
"After the death of Jesus, his followers - at the time a small sect of former Jews known as the Nazarenes - claimed he was the Messiah prophesied in Jewish texts and that he would soon return to fulfill the acts required of the Messiah. The majority of contemporary Jews rejected this belief and Judaism as a whole continues to do so today."
About.com's Guide to Islam explains Muslim beliefs as regards Jesus. In her article Do Muslims believe in the virgin birth of Jesus?, Huda writes:
"Muslims believe that Jesus (called 'Isa in Arabic) was the son of Mary, and was conceived without the intervention of a human father. The Qur'an describes that an angel appeared to Mary, to announce to her the "gift of a holy son" (19:19)."
"In Islam, Jesus is regarded as a human prophet and messenger of God, not part of God Himself. "
Most evidence for Jesus comes from the four canonical Gospels. Opinions differ on the validity of apocryphal texts like the Infancy Gospel of Thomas and the Proto-Gospel of James. Perhaps the biggest problem with the idea that Jesus is an historically verifiable figure for those who do not accept the validity of the Bible is the lack of corroborating evidence from the same period. The major ancient Jewish historian Josephus is usually cited as mentioning Jesus, yet even he lived after the crucifixion. Another problem with Josephus is the issue of tampering with his writing. Here are the passages attributed to Josephus said to help substantiate the historicity of Jesus of Nazareth.
"Now there was about this time Jesus, a wise man, if it be lawful to call him a man, for he was a doer of wonderful works, a teacher of such men as receive the truth with pleasure. He drew over to him both many of the Jews, and many of the Gentiles. He was the Christ, and when Pilate, at the suggestion of the principal men among us, had condemned him to the cross, those that loved him at the first did not forsake him; for he appeared to them alive again the third day; as the divine prophets had foretold these and ten thousand other wonderful things concerning him. And the tribe of Christians so named from him are not extinct at this day."
Jewish Antiquities 18.3.3
"But the younger Ananus who, as we said, received the high priesthood, was of a bold disposition and exceptionally daring; he followed the party of the Sadducees, who are severe in judgment above all the Jews, as we have already shown. As therefore Ananus was of such a disposition, he thought he had now a good opportunity, as Festus was now dead, and Albinus was still on the road; so he assembled a council of judges, and brought before it the brother of Jesus the so-called Christ, whose name was James, together with some others, and having accused them as lawbreakers, he delivered them over to be stoned."
Jewish Antiquities 20.9.1
Source: Did Josephus Refer to Jesus?
For further discussion of the historical validity of Jesus Christ, please read this discussion, which examines the evidence of Tacitus, Suetonius, and Pliny, among others.
Although our dating system refers to time before the birth of Jesus as B.C., for before Christ, it is now thought that Jesus was born a few years before our era. He is thought to have died in his 30s. It wasn't until A.D. 525 that the year of Jesus' birth was fixed (as we think, incorrectly). That was when Dionysius Exiguus determined Jesus was born eight days before a New Year's day in the year 1 A.D.
The date of his birth was long debated. In How December 25 Became Christmas, Biblical Archaeology Review (BAR) reports that at the start of the third century, Clement of Alexandria wrote:
"There are those who have determined not only the year of our Lord's birth, but also the day; and they say that it took place in the 28th year of Augustus, and in the 25th day of [the Egyptian month] Pachon [May 20 in our calendar]...And treating of His Passion, with very great accuracy, some say that it took place in the 16th year of Tiberius, on the 25th of Phamenoth [March 21]; and others on the 25th of Pharmuthi [April 21] and others say that on the 19th of Pharmuthi [April 15] the Savior suffered. Further, others say that He was born on the 24th or 25th of Pharmuthi [April 20 or 21]."2
The same BAR article says that by the fourth century December 25 and January 6 had gained currency. See The Star of Bethlehem and the Dating of the Birth of Jesus.