A few days ago on Sunday was the Feast of the Assumption of the Virgin Mary. Planty of information about it at ChurchYear.Net. Better late than never, I honor the day by posting a little Gregorian Chant for the Feast.
The official book of music for Mass is the Roman Gradual but there is a lesser known book, also official, that is meant for smaller churches that might find the more complicated melodies in the Roman Gradual to be too difficult. It's called the Gruaduale Simplex or Simple Gradual and an example can be viewed below. This is the introit or entrance antiphon from the Graduale Simplex, Assumpta Es Maria In Caelum:
Many of the antiphons in the Graduale Simplex were adapted from the Divine Office so anyone fortunate to sing the Liturgy of the Hours for the day might have sung this same melody.