The Nundinal letter is correctly calculated from the H of last year, see the detailed background history about NR Nundinae below.
See also: "Calendar".
There is no certified information at this point, but research made by pontifex Cn. Lentulus about the past calendars and Nundinal letters of Nova Roma indicate that the Nundinal letters for previous years were the following:
- 1998 Fl. Vedio M. Cassio cos. ‡ MMDCCLI a.u.c.. The Nundinal letter was F. Source: ML 1999-03-30
- 1999 L. Equitio Dec. Iunio cos. ‡ MMDCCLII a.u.c.. The Nundinal letter was HGA. The year started mistakenly as H (source: ML 1999-03-30), then later in the year, the incorrect H seems to have been changed from February to an equally incorrect G (source: Website 1999-02-10 and ML 1999-08-13, with explanation to the background of this confusion, an erroneous belief that the nundinal cycle had to be reset to start on the 8th day of the year, Jan. 8, H), then in October finally amended to the truly correct A (as shown here: Website 1999-10-07).
- 2000 Q. Maximo M. Minucio cos. ‡ MMDCCLIII a.u.c.. A bissextile (or leap) year. The Nundinal letter was AHC, but it should have been, including the bissextile switch, DC from A. The year started mistakenly as A, probably an update failure, and at the bissextile switch, after the day a.d. bis VI Kal. Mar., it changed automatically to H (source: Website 2000-02-29. There is a record of change, however, that it was modified to C at least from April (source: ML 2000-04-03 and Website 2000-05-12), probably resuming the correct calculation, which should have been D if it had continued the correct A for last year, and since it was a leap year, with a switch from D to C.
- 2001 Fl. Vedio (II) M. Cassio (II) cos. ‡ MMDCCLIV a.u.c.. The Nundinal letter was C, breaking the cycle. It should have been F from C. Source: NR Interactive Calendar 2001-09 Another source described that this new cycle was purposedly introduced and was derived as counted from the Declaration Day, pridie Kal. Mar. of 1998, through a virtual sequences 1998 C, 1999 F, 2000 AH, 2001 C: ML 2001-10-19
- 2002 M. Octavio L. Sulla (II) cos. ‡ MMDCCLV a.u.c.. The Nundinal letter was F, with regular continuance from the C of last year. It should have been A from F. Source: ML 2002-12-01
- 2003 K. Buteone T. Labieno cos. ‡ MMDCCLVI a.u.c.. The Nundinal letter can not be found for this year. The regular continuance would have been A from F, but according to the original (1998) lineage it should have been D from A. There is a third possibility, C, derived from next year which is F, and a fourth possibility, that the letter was left F, unchanged from last year, as an update failure.
- 2004 Cn. Salvio Cn. Equitio cos. ‡ MMDCCLVII a.u.c.. A bissextile (or leap) year. The Nundinal letter was marked F (but was technically FE). The regular continuance should have been DC from A. The nundinal cycle was broken again, and permanently so from now on, for unknown reason: a possible explanation might be that there was no update in the nundinal letter since 2002, F, and, due to failure in update, the same letter was repeated in 2003 and in 2004 as well. It is not marked in our source, but a switch must have had to occur from F to E after the day a.d. bis VI Kal. Mar.. The next year (marked H instead of A) certainly shows that this switch was, at least in the calculation for next year, observed. Source: NR Interactive Calendar 2004-01
- 2005 Fr. Apulo C. Laenate cos. ‡ MMDCCLVIII a.u.c.. The Nundinal letter was H, with regular continuance from the FE of last year. Source: ML 36798. This nundinal lineage is continued ever since in Nova Roma.
From 2004, the Nova Roman Nundinae continue an unbroken regular cycle. If we calculated backwards from this well established cycle that has been going on from 2004 to 2017, the result for the years prior 2004 would look the following:
- 1998 - E (it was F actually) -1 day difference from the original Nova Roman Nundinal cycle.
- 1999 - H (it was briefly H, as HGA actually) -1 day difference at least from the original Nova Roman Nundinal cycle.
- 2000 - CB (it was AC or AHC actually, but should have been DC) -1 day difference at least from the original Nova Roman Nundinal cycle.
- 2001 - E (it was C actually) +2 days difference from the actual, and +1 day difference from the original Nova Roman Nundinal cycle (which should have been F). The cycle was then restarted as if 1998 had been C.
- 2002 - H (it was F actually) +2 days difference from the actual, and +1 day difference from the original Nova Roman Nundinal cycle (which should have been A).
- 2003 - C (unknown, possibly left un-updated as F; the 1998 cycle should give D, the 2001 cycle should give A)
- 2004 - FE - in regular continuance up to 2017.
We can conclude that there have been 3 Nundinal cycles started within Nova Roma: the first in 1998, the second in 2001 and the third sometime around 2003-2004. The sequence of Nundinal letters for the 3 systems is the following:
started in 1998
started in 2001
started in 2004
|What it was|
|1998||F start of use||C||E||F|
|2000||DC end of use||AH||CB||AHC|
|2001||F||C start of use||E||C -3 days|
|2003||D||A end of use||C||-|
|2004||GF||DC||FE start of use||F +2 days (-1 day to 1st cycle)|
The automatic calculation of the annual sequence of the nundinae
This is how the nundinal letters would ideally follow each other year after year if there were no bissextile (leap) years:
A, D, G, B, E, H, C, F, A
The following list gives all possible bissextile year denotations with the nundinal switches after a.d. bis VI Kal. Mar., marked as the second letter in each doublets:
AH, DC, GF, BA, ED, HG, CB, FE
The following list places the bissextile doublets in the context of preceding and succeeding years. The letters in brackets show what year precedes and what year succeeds a given bissextile denomination:
(A) DC (F) AH (C) FE (H) CB (E) HG (B) ED (G) BA (D) GF (A)