At this council, the bishops of the Christian Church sought to establish a uniform system for determining the date of Easter. After much debate, the council decided that Easter would be celebrated on the first Sunday following the first full moon after the vernal equinox, which typically occurs around March 21st. This system ensured that Easter would fall on a Sunday, symbolizing the day of Christ's resurrection, while also connecting the celebration to the natural cycles of the moon and the spring season.

The decision was based on both Christian symbolism and the desire for a consistent system across the Christian world. The vernal equinox, which marks the point when day and night are equal in length, was chosen because it had agricultural and symbolic importance, signifying renewal and rebirth—an appropriate backdrop for the resurrection of Christ.

This decision by the Council of Nicaea has shaped how Easter is celebrated today, though variations still exist among different Christian denominations. The choice of the first Sunday after the first full moon following the equinox remains the standard in most of the Christian world, with the exception of some Eastern Orthodox churches, which use a different method based on the Julian calendar.

In summary, the determination of when Easter would be celebrated was formalized by the First Council of Nicaea in 325 AD, under the guidance of Emperor Constantine. This decision aimed to standardize the celebration across the Christian world, combining theological meaning with astronomical observation. shutdown123