NP was not a mark in the pre-Julian calendars, for it was apparently unknown to Varro and Ovid. Verrius Flaccus seems to have distinguished it from N, but his explanation is mutilated, even as it survives in Festus[23]. No one has yet determined for certain the origin of the sign, and discussion of the various conjectures would be here superfluous[24]. It appears to distinguish, in the Julian calendars, those days on which fell the festivals of deities who were not of an earthly and therefore doubtful character from those marked N. Thus in the series of _dies nefasti_ in February and April the Ides in each case have the mark NP as being sacred to Jupiter. EN. We have a mutilated note in the calendar of Praeneste which indicates what this abbreviation meant, viz. _endotercisus = intercisus_, i. e. ‘cut into parts’[25]. In morning and evening, as Varro tells us, the day was _nefastus_, but in the middle, between the slaying of the victim and the placing of the entrails upon the altar, it was _fastus_. But why eight days in the calendar were thus marked we do not know, and have no data for conjecturing. All the eight were days coming before some festival, or before the Ides. Of the eight two occur in January and two in February, the others in March, August, October and December. But on such facts no conjectures can be built. Q.R.C.F. (_Quando Rex Comitiavit Fas_) will be explained under March 24; the only other day on which it occurs is May 24. Q.St.D.F. (_Quando stercus delatum fas_) only occurs on June 15, and will there be fully dealt with. FP occurs thrice, but only in three calendars. Feb. 21 (_Feralia_) is thus marked in Caer.[26], but is F in Maff. April 23 (_Vinalia_) is FP in Caer. but NP in Maff. and F in Praen. Aug. 19 (_Vinalia rustica_) is FP in Maff. and Amit, F in Antiat. and Allif., NP in Vall. Mommsen explains FP as _fastus principio_, i. e. the early part of the day was _fastus_, and suggests that in the case of the _Feralia_, as the rites of the dead were performed at night, there was no reason why the earlier part of the day should be _nefastus_. But in the case of the two Vinalia we can hardly even guess at the meaning of the mark, and it does not seem to have been known to the Romans themselves. V. The Calendars still surviving. The basis of our knowledge of the old Roman religious year is to be found in the fragments of calendars which still survive. None of these indeed is older than the Julian era; and all but one are mere fragments. But from the fragments and the one almost perfect calendar we can infer the character of the earlier calendar with tolerable certainty.