Reverend Mother Gaius Helen Mohiam was a Bene Gesserit Reverend Mother. Mohiam trained the Lady Jessica in the Bene Gesserit chapterhouse on Wallach IX. Two decades later, Mohiam tested the young Paul Atreides before his departure for Arrakis with the gom jabbar. The test was to discover whether Paul was "truly human" by trial of pain, using a small box that Paul placed his hand inside. The pain inflicted on Paul was caused by nerve induction and clearly drained an incredible amount of energy from the Reverend Mother, since no male or female child had ever withstood that much physical pain before.
Mohiam joined the conspiracy to topple the rule of Paul Atreides after he ascended the Golden Lion Throne and unleashed his Jihad upon the Empire. She, along with Scytale (a Tleilaxu Face Dancer), Edric (a Guild Navigator), and Irulan Corrino (embittered wife of Paul Atreides), plotted to insinuate, as the Emperor's Reverend Mother, the Tleilaxu ghola Hayt into the court to weaken Paul's confidence in his prescience and thereby ruin him. When the plot failed, she was executed in the retaliation initiated by Alia Atreides after Paul walked into the desert after the death of Chani, ignoring Paul's instructions that Mohiam be spared.
Images of Gaius Helen Mohiam
Behind the Scenes
Reverend Mother Mohiam was played by Siân Phillips in David Lynch's adaptation and Zuzana Geislerová in the 2000 miniseries and its sequel Children of Dune. Charlotte Rampling portrays her in Denis Villenueve's 2021 movie and was interested in portraying Lady Jessica in Alejandro Jodorowski's production. She eventually turned the role down due to a scene that involved 2,000 extras defecating at once.
The prequel novels by Brian Herbert and Kevin J. Anderson reveal that Mohiam was secretly the mother of Jessica and grandmother of Paul. The lineage occurred as a result of a vicious rape by the Baron Harkonnen, although she had already been commanded by the Sisterhood to become pregnant with the Baron's daughter for their breeding program. In revenge for the attack, she gave the Baron a degenerative disease that he covered up through his gluttony. According to Herbert and Anderson, this twist was discovered in notes left behind by Frank Herbert.
However, Lady Jessica would have known the true identity of her mother through Other Memory when she took the Water of Life. So too, Alia would have known her grandmother's true identity, as would have Paul, Leto II, and Ghanima. None of these individuals mentioned Mohiam in this context, although this may be the reason that Paul left instructions that she be spared.