The Historical Illuminatus Chronicles is a series of three novels by Robert Anton Wilson written after his highly successful The Illuminatus! Trilogy and his 1981 Masks of the Illuminati. His co-author from the first trilogy, Robert Shea, was not involved in this series, providing only a praising blurb.

It is composed of three books: The Earth Will Shake (1982), The Widow's Son (1985) and Nature's God (1991). A fourth book, The World Turned Upside Down, was promised at the end of Nature's God but was never written; Wilson also had stated he intended the Chronicles to be a pentalogy.[1] His death in 2007 left the series as a trilogy, incomplete. There is an audiobook of the first novel read by Scott Crisp.[2]

It concerns the adventures of Sigismundo Celine, an ancestor of the Hagbard Celine character from the Illuminatus! Trilogy, as he blunders through Europe and America during the Enlightenment, constantly fighting to escape becoming a part of history.

In the first book, Sigismundo is an adolescent in Naples, Italy, where his uncle introduces him to the teaching of the Freemasons. In the second book Sigismundo has been banished from Naples because of a lovers' duel. He lives in Paris and is taken captive twice. The first time he is imprisoned in the Bastille, from which he escapes using Masonic techniques of concentration to help distract himself from the pain involved in climbing down from his tower. The second time Sigismundo is imprisoned by a more mysterious group of captors, who seek to convince him that he is a descendant of Jesus Christ. In the third book, Sigismundo finds himself in further exile, in the wilderness of North America.

Throughout history, secret societies have played a crucial role in shaping events that have created our world. Only an inner circle of power elite know the full extent of the influence of the conspiracy. It is Paris, 1772, and Sigismundo Celine knows he is destined to play an important part in this history-behind-history. The masons, the English nobility, the Jabobites, the Rosicrucians, the ruling clique of pre-Revolution France: these are but a few of the factions involved in the machinations and intrigue in which Sigismundo has become enmeshed.Thrown into the Bastille, shot at, assaulted by assassins, tortured, and brutally interrogated, he knows only what he is and what he must do to become the one spoken of in the old texts. But what he doesn't know could kill him: the secret powers of Maria, the Italian beauty who has become an English Lady; the Irish fisherman, Moon, who stumbles across the inner workings of an unsuspected cult; and the question they keep asking: the identity of The Widow's Son. "The real history of Western Civilization, where our heroes (and anti-heroes), the Illuminati, roam the night." — Jonathan Sellers, Antiquities of the Illuminati "A masterful satirist who views history as an open question." - Brad Linaweaver, Atlanta Constitution "More important than Ulysses or Finnegans Wake." — Timothy Leary