Notes for the Life of Christ Timeline.
Both Mauro and Ussher agree basically on the BC dates for the birth of Christ and His baptism. Mauro follows the common idea that Christ’s public ministry began immediately after His baptism/temptation putting Jesus at about 33 1/2 years of age when He was crucified. Ussher believes there were 2 - 3 years between the baptism of Christ and His beginning His public ministry putting Jesus at about 36 1/2 years of age when He died. Here the explanation from the editor of Ussher:
“It is the common belief that Jesus was thirty-three years old when He died. This is based on the assumption that he started His ministry when He was thirty. [Luke 3:23] Luke was a very precise historian. If Jesus had been thirty years old, he would not have said about thirty. Based on that text, the only thing we can say for certain is the Jesus was not thirty years old at the start of His ministry. However, He was likely about thirty when He was baptized by John the Baptist in 26 AD. About three years elapsed between His baptism and the start of His public ministry in 29 AD. According to what we know about when He was born, He would have been thirty-six years old when He died. The 33 AD date is also confirmed by John [John 2:20] for this establishes the date of the first passover of Christ at 30 AD, forty-six full years after Herod started to rebuild the temple in 17 BC.” Ussher, pg. 822-823