Liber Ivonis

Current Holder: Georgiana Wentworth

Origin: Recovered from the Vault of Echoes, Orphean Society Building, London (Chapter 1)

Physical Description

A Latin manuscript, quarto format, bound in dark calfskin that has been rebound at least once. The pages are heavy vellum with occasional illuminated capitals in faded red and blue ink. Several sections bear marginalia in multiple hands spanning what appears to be centuries of scholarly annotation. The binding is sound but the spine is cracked at two points from heavy use.

Provenance

Recovered from the Vault of Echoes in the Orphean Society Building during the Chapter 1 London investigation. The Vault also contained The Book of Eibon and the Massa di Requiem per Shuggay. The Liber Ivonis is the Latin translation of the original Book of Eibon, attributed to Caius Philippus Faber in the 13th century. This copy appears to date from the 16th or 17th century.

CoC 7e Tome Statistics

(Source: CoC 7e Keeper Rulebook, Mythos Tomes)

Campaign Relevance — The Harmonic Binding Connection

The Liber Ivonis is the party’s most important research text for understanding the Harmonic Engine. As established in the Session 11 assault planning scene, the tome contains:

• Fragmentary references to “harmonic binding” rituals — the use of sustained tones to create dimensional weak points. These are not complete ritual instructions but theoretical descriptions of how sound can be used to thin the boundaries between spaces.
• The A=432 Hz frequency in annotations. This is not standard musical pitch (A=440 Hz in modern tuning, lower in period tuning). It is a frequency associated with geometric resonance — the same frequency the fork is tuned to. The annotations connect this frequency to angular geometry, the mathematics of intersecting planes.
• The fork-Engine-Hound connection. The harmonic binding described in the Liber Ivonis operates on the same principles as the Hound of Tindalos — angular geometry made audible. The Engine is a device that generates sustained harmonic binding at scale. The fork is a hand-held version of the same principle. Katherine’s unshared fork vision (Session 9) perceived exactly this connection.

Known Uses in Play

• Chapter 1: Recovered from the Vault of Echoes.
• Session 4: Stolen from the party’s rooms at Palais Kinsky during the Polizeidirektion search.
• Session 10: Recovered from the Polizeidirektion using Metternich’s writ.
• Session 11 (planned): Available for Georgiana’s research during assault planning. Partial study yields the harmonic binding intelligence described above.

Session 12 Update — Studied at Thaliastraße 12 (11 August 1814)

Georgiana studied the Liber Ivonis during the forbidden texts study session at Thaliastraße 12 on 11 August.

Intelligence Revealed

• Harmonic gate theory: The text confirmed the theoretical basis for the Engine’s function. Sustained harmonic tones at precise frequencies create dimensional weak points, thinning the boundary between spaces.
• 432 Hz as the resonant key: The text’s annotations identify this specific frequency as tied to Yog-Sothoth’s domain. This corroborates what the Adler interrogation established and gives the counter-ritual plan a firm theoretical foundation.

Sanity Cost

Georgiana suffered temporary madness during the study: laughing and crying uncontrollably, unable to stop. The episode passed. The intelligence survived. The cost was real.

Known Uses in Play (Updated)

• Chapter 1: Recovered from the Vault of Echoes.
• Session 4: Stolen from the party’s rooms at Palais Kinsky during the Polizeidirektion search.
• Session 10: Recovered from the Polizeidirektion using Metternich’s writ.
• Session 12: Studied by Georgiana on 11 August. Yielded harmonic gate theory and the 432 Hz confirmation. Georgiana suffered temporary madness during study.