Dominical Letter - Dominical Letter of A Date

Dominical Letter of A Date

The days of the year from 1 January to 31 December are marked with a continuous recurring cycle of seven letters: A, B, C, D, E, F, G. A is always set against 1 January, B against 2 January, C against 3 January, and so on. Thus F falls to 6 January, G to 7 January; A again recurs on 8 January, and also, consequently, on 15 January, 22 January, and 29 January. Continuing in this way, 30 January is marked with a B, 31 January with a C, and 1 February with a D. This is carried on through all the days of an ordinary year (i. e. not a leap year). Thus D corresponds to 1 March, G to 1 April, B to 1 May, E to 1 June, G to 1 July, C to 1 August, F to 1 September, A to 1 October, D to 1 November, and F to 1 December — a result which Durandus recalled by the following distich:

Alta Domat Dominus, Gratis Beat Equa Gerentes

Contemnit Fictos, Augebit Dona Fideli.

Another one is:

Add G, beg C, fad F.

Yet another:

At Dover dwell George Brown, Esquire; Good Christopher Finch; and David Fryer.

Clearly, if 1 January is a Sunday, all the days marked by A will also be Sundays; If 1 January is a Saturday, Sunday will fall on 2 January which is a B, and all the other days marked B will be Sundays; if 1 January is a Monday, then Sunday will not come until 7 January, a G, and all the days marked G will be Sundays.

Traditionally, the Catholic ecclesiastical calendar treats 24 February as the day added, as this was the Roman leap day, with events normally occurring on 24–28 February moved to 25–29 February. The Anglican and civil calendars treat 29 February as the day added to leap years, and do not shift events in this way.