"[T]he seasons of the year are themselves transformed from the pagan Spring, Summer, Autumn, and Winter to the Christian Advent, Christmas, Epiphany, Lent, Passiontide, Easter, and Pentecost.
"However, because the sun itself in both its daily and annual course is seen as a type of Christ, the Sun of Justice, the Christian Year is rather significantly integrated with the cycle of the sun. The Christian Year begins about four weeks before Christmas, which coincides approximately with the Winter Solstice--the time when, in the Northern Hemisphere, the sun is at its lowest meridian and is about to begin once more its upward journey to the midheaven. Anciently this time was sometimes known as the Birth of the Sun, being, as it were, the midnight of the year, from which point the sun begins to rise. According to tradition, then, Christ was born at midnight at the Winter Solstice."
--Alan Watts, Myth and Ritual in Christianity, p. 87.
"The Vernal Equinox, corresponding in the daily cycle to sunrise, is the approximate Season of Easter, the feast of Christ's Resurrection, the actual day of Easter being the Sunday following the first full moon after the Vernal Equinox. As the sun climbs to the midheaven after the equinox, the Church celebrates--forty days later--the Ascension of Christ into heaven, and in another ten days Pentecost or Whitsunday, the feast of the descent of the Fire of the Holy Spirit upon the Church. The solar symbolism is obvious, except that the Church keeps no seasonal feast at the Summer Solstice, and observes only the course of the sun in its rising." --p. 88
"However, because the sun itself in both its daily and annual course is seen as a type of Christ, the Sun of Justice, the Christian Year is rather significantly integrated with the cycle of the sun. The Christian Year begins about four weeks before Christmas, which coincides approximately with the Winter Solstice--the time when, in the Northern Hemisphere, the sun is at its lowest meridian and is about to begin once more its upward journey to the midheaven. Anciently this time was sometimes known as the Birth of the Sun, being, as it were, the midnight of the year, from which point the sun begins to rise. According to tradition, then, Christ was born at midnight at the Winter Solstice."
--Alan Watts, Myth and Ritual in Christianity, p. 87.
"The Vernal Equinox, corresponding in the daily cycle to sunrise, is the approximate Season of Easter, the feast of Christ's Resurrection, the actual day of Easter being the Sunday following the first full moon after the Vernal Equinox. As the sun climbs to the midheaven after the equinox, the Church celebrates--forty days later--the Ascension of Christ into heaven, and in another ten days Pentecost or Whitsunday, the feast of the descent of the Fire of the Holy Spirit upon the Church. The solar symbolism is obvious, except that the Church keeps no seasonal feast at the Summer Solstice, and observes only the course of the sun in its rising." --p. 88