From Wikipedia, the free encyclopedia.
Trinity Sunday is the first Sunday after Pentecost in the Christian liturgical calendar.
In the Roman Catholic Church it is officially known as the Solemnity of the Most Holy Trinity and prior to the reforms of the Second Vatican Council it marked the end of a three-week period (beginning on Rogation Sunday, the fifth Sunday after Easter) when church weddings were forbidden (other such times included the period from the first Sunday of Advent through the end of the Octave of Epiphany, or January 13, and Septuagesima Sunday through Low Sunday, the first Sunday after Easter).
The Thursday after Trinity Sunday is observed as the Feast of Corpus Christi, except in the United States, when it falls on the following Sunday instead. After Corpus Christi, green vestments are worn by the priest and celebrants for the rest of the liturgical year, until Advent begins, except on certain special days, including those designated as a holy day of obligation.