DOMINICAL LETTER

For the purpose of exhibiting the day of the week corresponding to any given day of the year, the framers of the ecclesiastical calendar denoted the seven days of the week by the first seven letters of the alphabet. A, B, C, D, E, F, and G; and placed these letters in a column opposite to the days of the year, in such a manner that A stood opposite the 1st of January or first day of the year, B opposite the 2d, and so on to G, which stood opposite the 7th; after which A returns to the 8th, and so on through the 365 days of the year. Now if one of the days of the week, Sunday, for example, falls opposite to E, Monday will be opposite F, Tuesday G, Wednesday A, and so on; and every Sunday through the year will be represented by the same letter E, every Monday by F, and so on. The letter which represents Sunday is called the Dominical Letter, or Sunday/ Letter. As the number of days in the week and the number in the year are prime to each other, two succe ive years cannot begin with the same day; hence the Dominical Letter changes every year. This mode of representing the days of the week has now fallen nearly into desuetude, and the initial letter of the name of the day is placed in our almanacs opposite the day of the month. [s. 372]