Apart from the surviving Fasti, we have to depend, both for the completion of the religious calendar, and for the study and interpretation of all its details, chiefly on the fragmentary remains of the works of the two great scholars of the age of Julius and Augustus, viz. Varro and Verrius Flaccus, and on the later grammarians, commentators, and other writers who drew upon their voluminous writings. Varro’s book _de Lingua Latina_, though not complete, is in great part preserved, and contains much information taken from the books of the pontifices, which, did we but possess them, would doubtless constitute our one other most valuable record besides the _Fasti_ themselves[42]. Such, too, is the value of the dictionary of Verrius Flaccus, which, though itself lost, survives in the form of two series of condensed excerpts, made by Festus probably in the second century, A.D., and by Paulus Diaconus as late as the beginning of the ninth[43]. Much of the work of Varro and Verrius is also imbedded in the grammatical writings of Servius the commentator on Virgil, in Macrobius, Nonius, Gellius, and many others, and also in Pliny’s _Natural History_, and in some of the Christian Fathers, especially St. Augustine and Tertullian; but all these need to be used with care and caution, except where they quote directly from one or other of their two great predecessors. The same may be said of Laurentius Lydus[44], who wrote in Greek a work _de Mensibus_ in the sixth century, which still survives. To these materials must be added the great historical writers of the Augustine age; Livy, who, uncritical as he was, and incapable of distinguishing the genuine Italian elements in religious tradition from the accretions of Greek and Graeco-Etruscan myth, yet supplies us with much material for criticism; and Dionysius of Halicarnassus, who as a foreigner resident for some time in Rome, occasionally describes ritual of which he was himself a witness. The Roman lives of Plutarch, and his curious collection entitled _Roman Questions_, also contain much interesting matter, taken from several sources, e.g. Juba, the learned king of Mauritania, but as a rule ultimately referable to Varro. Beyond these there is no one author of real importance; but the ‘plant’ of the investigator will include of course the whole of Roman literature, and Greek literature so far as it touches Roman life and history. Of epigraphical evidence there is not much for the period of the Republic, beyond the fragments of the Fasti; by far the most valuable Italian religious inscription is not Roman but Umbrian; and the _Acta Fratrum Arvalium_ only begin with the Empire. Yet from these[45], and from a few works of art, however hard of interpretation, some light has occasionally been thrown upon the difficulties of our subject; and the study of early Italian culture is fast progressing under the admirable system of excavation now being supervised by the Italian government.