A missal provides all the prayers, hymns, and readings necessary for the celebration of Mass over the course of the year. This deluxe 15th-century missal made for use on the altar was given to the church of St Lawrence in London by William Melreth, alderman, textile merchant of Broad Street and eventually member of Parliament, probably just before he served as Sheriff of London. Two calendars run side-by-side for church services. One calendar is arranged around Christmas and Easter (Advent, Lent, Pentecost). The other is a calendar of dates on which saints and some events are remembered. The Annunciation to the Virgin is one of the latter, celebrated since early in the history of Christianity on 25 March. Its date is independent of the Easter calendar, and often it falls within Lent, the weeks of fasting and prayer preceding Easter. Masses during Lent have solemn prayers, hymns with joyous 'Allelluia' being cut. Missals usually present a 'Plan B' in case it falls outside of Lent. The first letter of the prayers for mass has a picture of the Archangel Gabriel bearing a scroll with the words "Ave Maria" beside the Virgin, taken away from her prayerbook by the message.