What year did the holy spirit first come down?

Year 30 on May 29 hope this helped

Christianity became a religioin 2000 years ago, which was when Jesus was walking the earth..
Jesus was 30 years old when he died, and most likely 30 years old when he was baptized by John the Baptist when the holy spirit descended on him like a dove (I believe that's the first time the Holy spirit is mentioned in the NT)...

Do the rest of the math that goes with that! Best I can do.