... Holy-days for which Proper Lessons are appointed in the Table fall upon a Sunday which is the first Sunday in Advent, Easter-day, Whitsunday, or Trinity Sunday, the Lessons appointed for such Sunday shall be read, but if it fall upon any other Sunday, the Lessons appointed either for the Sunday or for the Holy-day may be read at the discretion of ... — The Book of Common Prayer - and The Scottish Liturgy • Church of England