William James Miller, The American Church Dictionary and Cyclopedia
“ Ash Wednesday—The first day of Lent; one of the two absolute Fast Days of the Church, the other being Good Friday. In ancient times the first day of Lent was called Caput Jejunii, i.e., "Head of the Fast," because Lent began on that day. It was also called Dies Cinerum, i.e., "Day of Ashes," from the custom of placing ashes on the head of penitents who presented themselves before the Bishop on this day. Ash Wednesday is a day of deep devotion, of prayer, fasting, self-examination and confession of sin. The public services are most solemn ”
