Vegoia (Etruscan: Vecu) is a sibyl, prophet, or nymph within the Etruscan religious framework who is identified as the author of parts of their large and complex set of sacred books, detailing the religiously correct methods of founding cities and shrines, draining fields, formulating laws and ordinances, measuring space and dividing time; she initiated the Etruscan people to the arts, as originating the rules and rituals of land marking, and as presiding over the observance, respect, and preservation of boundaries. Vegoia also is known as Vecu, Vecui, and Vecuvia,^[1] as well as Vegoe; her name is also given as Begoe or Bigois.

The Etruscan religious system remains mostly obscure. There being few bilingual documents comparable to the Rosetta stone that could facilitate translation, the Etruscan language is poorly understood. Therefore, the existing ancient Etruscan documents of the eighth, seventh, and sixth centuries BCE that would reveal their religious concepts, do not yield much. Moreover, during the later period of the fifth through the first centuries BCE, Etruscan civilization heavily absorbed elements of Greek civilization and eventually, it was diluted in the Greco-Roman cultural mix with their powerful Roman neighbors. Lastly, while the Etruscans formalized their religious concepts and practices in a series of "sacred books", most no longer exist and they are known only through commentaries or quotes by Roman authors of the late first century,^{[lower-alpha 1]} and hence, may be biased.

Two mythological figures have been set by the Etruscans as presiding over the writing of their sacred books: Vegoia, the subject of this article, and Tages, a monstrous childlike figure gifted with the knowledge and prescience of an ancient sage. Those books are known from Latin authors under a classification pertaining to their content according to their mythological author (whether delivered through speeches or lectures, such as Tages, or inspiration).^{[3][lower-alpha 2]}

The figure of Vegoia is almost entirely blurred in the mists of the past. She is known mostly from the traditions of the Etruscan city of Chiusi (Latin: Clusium; Etruscan: Clevsin; Umbrian: Camars) (now in the province of Siena). The revelations of the prophetess Vegoia are designated as the Libri Vegoici that included the Libri Fulgurales and part of the Libri Rituales, especially the Libri Fatales.

She is barely designated as a "nymph" and as the author of the Libri Fulgurales,^[5] that give the keys to interpreting the meaning of lightning strokes sent by the deities using a cartography of the sky that, as a sort of property division and use assignment, is attributed to Vegoia.^[6]: 25 Her assignment of sectors of the horizon to various deities is paralleled in the microcosm that is interpreted using the liver of a sacrificed animal. The sacred divisions also seem to have a correspondence in the measurement and division of land that, since the very dawn of Etruscan history, obeyed religious rules.^[6]: 13 Her dictates taught the correct methods of measuring space.^{[lower-alpha 3]}

Vegoia also was depicted as lording over the observation of these rules, to be upheld under threat of dire woe or malediction.^[6]: 13 Thus, she was established as the power presiding over land property and land property rights, laws, and contracts (as distinct from commercial contract laws).

She also is indicated as having established the laws relative to hydraulic works,^[6]: 4 thus having a special relationship to "tamed" water.

This imposing system of "revealing" and "sacred texts" left a significant imprint on the neighboring Italic peoples. There is ample evidence of the Etruscan culture having heavily permeated the less-advanced communities of their Latin and Sabine neighbours. For example, the Etruscan alphabet that was derived from the Greek one, is solidly established as having inspired the Latin alphabet. The principles and structural rules of the Etruscan decimal numeral system, likewise, are recognized as the origin of the Roman numerals that are a simplified version of the Etruscan system. Similarly derived are the symbols of supreme power (see Etruscan civilization), the structure of the Roman calendar,^{[lower-alpha 4]} and the Etruscan Craeci is the source for the word "Greeks" (who self-identified as Hellenes), etc.^[8]

Likewise, one may suspect that the legend of Egeria is related to Vegoia. Egeria is the name of the nymph who inspired the second legendary king of Rome, Numa Pompilius (in Latin, "numen" designates "the expressed will of a deity"),^[2]: 47 who succeeded its founder, Romulus, when she dictated to him the rules that established the original framework of laws and rituals of Rome that also are associated with "sacred books".

Numa is reputed to have written down the teachings of Egeria in "sacred books" that he caused to be buried with him. According to Plutarch, when a chance accident brought them back to light some 500 years later, the books were deemed by the Roman Senate to be inappropriate for disclosure to the people and they ordered that the books be destroyed.^[9] What made these sacred books 'inappropriate' was certainly of a "political" nature, but precisely what that was, had not been handed down by Valerius Antias, the source that Plutarch was using. However, sacred books were the source used to interpret the abstruse omens of deities (episode of the omen from Faunus^[2]: 377). Sacred books also were associated with beneficial water, which also would have been linked to Vegoia.

• List of Etruscan mythological figures