Most people would assume that Jesus was born in the year 1 A.D., but that is probably not correct. Most scholars and historians (including conservative ones) place the year of the birth of Jesus around 5 B.C. Of course B.C. stands for before Christ, so how could Christ be born before Christ?
It seems that when the calendar was set up it was miscalculated by about five years. Herod the Great reigned from 37 B.C.-4 B.C. and Jesus was born during his reign. Since Herod died in 4 B.C., Jesus had to be born in 4 B.C. or earlier. So Jesus was probably born around 5 B.C.
