Is it true?
What do historians agree happened?
A short list of facts that most scholars accept, whatever they believe.
Historians work with probabilities. They ask which events are best supported by early and independent sources. For Jesus, a few facts come out at the top of that list.
Two facts have almost universal agreement: John the Baptist baptised Jesus, and the Romans crucified Him under Pontius Pilate. Most scholars also accept that He was a Jewish teacher from Galilee, that He called disciples, and that He caused a stir at the Temple in Jerusalem.
Then there is what happened after His death. Historians cannot test a miracle. What they can say is that, very soon after the crucifixion, His followers sincerely believed they had seen Him alive again, and that this belief has broad support among New Testament scholars.
Some Christian scholars, most of all Gary Habermas, build their case for the resurrection only on facts like these, which they say even critical scholars grant. This is often called the minimal facts approach. It is worth knowing that the list of facts and the claim of wide agreement come from Habermas's own survey, so treat it as one scholar's summary and check the sources for yourself.
Baptised by John
Jesus's baptism by John the Baptist is one of only two events with near-universal scholarly agreement. The scholar James Dunn ranks it among the most certain facts we have about Jesus.
Sources
Crucified under Pontius Pilate
This is the other near-certain fact. Christian sources say it, and so does the Roman historian Tacitus.
Sources
A Jewish teacher from Galilee
Most scholars also accept that He came from Nazareth, taught in parables, gathered disciples and caused a controversy at the Temple, though with less certainty than the baptism and crucifixion.
Sources
His followers believed they saw Him alive
That the disciples believed they had seen the risen Jesus has broad support in New Testament scholarship. Scholars disagree about what caused that belief.
Sources
The minimal facts approach
Gary Habermas argues for the resurrection using only facts he says the vast majority of critical scholars accept. It is a Christian argument, and his claim about how many scholars agree is his own.
Sources
My verses
In those days Jesus came from Nazareth in Galilee and was baptized by John in the Jordan. As soon as Jesus came up out of the water, He saw the heavens breaking open and the Spirit descending on Him like a dove. And a voice came from heaven: “You are My beloved Son; in You I am well pleased.”
And wishing to satisfy the crowd, Pilate released Barabbas to them. But he had Jesus flogged, and handed Him over to be crucified.
In the fifteenth year of the reign of Tiberius Caesar, while Pontius Pilate was governor of Judea, Herod tetrarch of Galilee, his brother Philip tetrarch of Ituraea and Trachonitis, and Lysanias tetrarch of Abilene, during the high priesthood of Annas and Caiaphas, the word of God came to John son of Zechariah in the wilderness.
For what I received I passed on to you as of first importance: that Christ died for our sins according to the Scriptures, that He was buried, that He was raised on the third day according to the Scriptures, and that He appeared to Cephas and then to the Twelve. After that, He appeared to more than five hundred brothers at once, most of whom are still living, though some have fallen asleep. Then He appeared to James, then to all the apostles. And last of all He appeared to me also, as to one of untimely birth.
God has raised this Jesus to life, to which we are all witnesses.
Further reading
Links open independent sources, not church websites.