First Council of Nicaea (325 AD)

325 AD (May–August) • First ecumenical council of the Christian Church
Called by Emperor Constantine I • Held in Nicaea (today İznik, Turkey)
Main result: Nicene Creed – Jesus is fully divine (against Arianism)

Jesus birth: scholars say ~6–4 BC

Years passed by 325 AD:
• 6 BC → ~330 years
• 4 BC → ~328 years
(no year 0 → subtract 1)

Roughly three centuries after Christ.

No. Not even close.

AD system → invented ~525 AD by Dionysius Exiguus (miscalculated slightly)
December 25 Christmas → first clear evidence ~336 AD in Rome

They only standardized Easter date calculation (first Sunday after first full moon after March 21 Julian).

~328–330 years after Jesus was born, the church held its first big meeting to define if Jesus is really God — and no, they didn't invent Christmas or the calendar.