Fasti in the context of Aemilia (gens)

The Fasti (Latin: Fāstī [ˈfaːstiː], "the Calendar"), sometimes translated as The Book of Days or On the Roman Calendar, is a six-book Latin poem written by the Roman poet Ovid and made public in AD 8. Ovid is believed to have left the Fasti incomplete when he was exiled to Tomis by the emperor Augustus in 8 AD. Written in elegiac couplets and drawing on conventions of Greek and Latin didactic poetry, the Fasti is structured as a series of eye-witness reports and interviews by the first-person vates ("poet-prophet" or "bard") with Roman deities, who explain the origins of Roman holidays and associated customs—often with multiple aetiologies. The poem is a significant, and in some cases unique, source of fact in studies of religion in ancient Rome; and the influential anthropologist and ritualist J.G. Frazer translated and annotated the work for the Loeb Classical Library series. Each book covers one month, January through June, of the Roman calendar, and was written several years after Julius Caesar replaced the old system of Roman time-keeping with what would come to be known as the Julian calendar.

The popularity and reputation of the Fasti has fluctuated more than that of any of Ovid's other works. The poem was widely read in the 15th–18th centuries, and influenced a number of mythological paintings in the tradition of Western art. However, as scholar Carole E. Newlands has observed, throughout the 20th century "anthropologists and students of Roman religion … found it full of errors, an inadequate and unreliable source for Roman cultic practice and belief. Literary critics have generally regarded the Fasti as an artistic failure." In the late 1980s, however, the poem enjoyed a revival of scholarly interest and a subsequent reappraisal; it is now regarded as one of Ovid's major works, and has been published in several new English translations. Ovid was exiled from Rome for his subversive treatment of Augustus, yet the Fasti continues this treatment—which has led to the emergence of an argument in academia for treating the Fasti as a politically weighted work.

In ancient Roman religion, the Fordicidia was a festival of fertility, held on the Ides of April (April 15), that pertained to farming and animal husbandry. It involved the sacrifice of a pregnant cow to Tellus, the ancient Roman goddess of the Earth, in proximity to the festival of Ceres (Cerealia) on April 19.

On the Roman religious calendar, the month of April (Aprilis) was in general preoccupied with deities who were female or ambiguous in gender, opening with the Feast of Venus on the Kalends. Several other festivals pertaining to farm life were held in April: the Parilia, a feast of shepherds, on April 21; the Robigalia on April 25, to protect crops from blight; and the Vinalia, one of the two wine festivals on the calendar, at the end of the month. Of these, the Fordicidia and Robigalia are likely to have been of greatest antiquity. William Warde Fowler, whose early 20th-century work on Roman festivals remains a standard reference, asserted that the Fordicidia was "beyond doubt one of the oldest sacrificial rites in Roman religion."

The nundinae (/nənˈdɪnaɪ/, /-niː/), sometimes anglicized to nundines, were the market days of the ancient Roman calendar, forming a kind of weekend including, for a certain period, rest from work for the ruling class (patricians).

The nundinal cycle, market week, or eight-day week (Latin: nundinum or internundinum) was the cycle of days preceding and including each nundinae. These were marked on fasti using nundinal letters from A to H. The earliest form of the Roman calendar is sometimes said to have included exactly 38 such cycles, running for 304 days from March to December before an unorganized expanse of about 50 winter days. The lengths of the Republican and Julian calendars, however, were not evenly divisible by 8; under these systems, the nundinae fell on a different letter each year. These letters formed the basis of the later Christian dominical letters.

A menologium rusticum (pl. menologia rustica), also known by other names, was a publicly displayed month-by-month inscription of the Roman calendar with notes on the farming activities appropriate for each part of the year. Two versions were recovered in Rome during the Italian Renaissance, the Menologium Rusticum Colotianum and the Menologium Rusticum Vallense. The first is now held by the Naples Museum and the second has been lost. Both of the known examples of the style appear to copy a separate original, include a sundial for tracking the hours of the day, and prominently display astrological information for each month. The original was probably carved sometime during the 1st century. In addition to these pillar-style menologia, the name is also sometimes applied to fasti and other wall calendars that include similar agricultural details in their coverage of the year.

Polemius Silvius (fl. 5th century) was the author of an annotated Julian calendar that attempted to integrate the traditional Roman festival cycle with the new Christian holy days. His calendar, also referred to as a laterculus or fasti, dates to around 448–449. He was active in southeastern Gaul.

A laterculus was, in late antiquity or the early medieval period, an inscribed tile, stone or terracotta tablet used for publishing certain kinds of information in list or calendar form. The term thus came to be used for the content represented by such an inscription, most often a list, register, or table, regardless of the medium in which it was published. A list of soldiers in a Roman military unit, such as of those recruited or discharged in a given year, may be called a laterculus, an example of which is found in an inscription from Vindonissa. The equivalent Greek term is plinthos (πλίνθος; see plinth for the architectural use).

A common type of laterculus was the computus, a table that calculates the date of Easter, and so laterculus will often be equivalent to fasti. Isidore of Seville said that a calendar cycle should be called a laterculus "because it has the years put in order by rows," that is, in a table.