On this, the Seventh Day of Christmas the song says the true love gives "seven swans a-swimming." The meaning behind the seven swans is they represent the seven gifts of the Holy Ghost. Isaiah 11:2-3 - wisdom, understanding, counsel, fortitude, knowledge, piety, and fear/respect of the Lord.
Saint of the Day - St. Sylvester I - pope from 314 - 335. If you know your history at all, this was both before and after the Edict of Milan and the emergence of the Church from the catacombs and with Emperor Constantine, the building of some of the greatest basilicas - like St. John Lateran and St. Peter's. He was also the pope during the Council of Nicaea. He was in charge at the end of the persecution of the Church and into the freedom of the Church.