The 39 Clues Wiki
The 39 Clues Wiki

Olivia Behan Cahill was the widow of Gideon Cahill. She was one of the first Cahills. She was the one to start developing a Serum Antidote.


Olivia Behan Cahill married Gideon Cahill and had five children (Madeleine was born after Gideon died). Her home was destroyed and her husband was killed in an explosion that Gideon set to stop Damien Vesper from getting his research. She was pregnant with her fifth child, Madeleine, at the time. Her four oldest children were scattered around the globe, and she taught Madeleine that reuniting the family was the most important thing. In 1526, Olivia died, according to the book Vespers Rising. However in the book Into the Gauntlet, at the end of the clue hunt the Cahills find a record from Olivia Cahill's original accounts that describes her desire for the family to be re-united and suggests that Olivia Cahill survived for long enough to hear back from Madeleine of her children's deaths.

Olivia taught Madeleine all the skills of the other four founders. Every time Madeleine does well she uses one of these expressions to praise Madeleine:

a jot of Jane - praising an artistic accomplishment

a cut of Katherine - to praise an intellectual victory

a touch of Thomas - praising an athletic achievement

a lick of Luke - to praise a strategic success

magnificence of Madeleine- if something else was done well


Into the Gauntlet[]

Within the Madrigal Stronghold on Cahill Island the Cahills find a translation from Olivia Cahill's accounts. In it, Olivia Cahill reminisces on happy times with her family around the dining table prior to the fire of 1507, and discusses her hopes for family reunification. In a later entry she notes that Madeleine has brought her news of her childrens' deaths around the globe. She discusses her fear that her family will unleash devastation on the world at large, and her hope that one day descendants from each branch of the Cahill family will meet at the table and the Cahill family will be at peace. Olivia's wish finally comes true at the end of the clue hunt when all the Cahill branches decide to make amends after Amy and Dan stop Isabel Kabra from taking the Master Serum.

Vespers Rising[]

Part Two - Madeleine Cahill[]

Olivia (Babbitt) is first shown after her daughter, Madeleine attacks "an old buzzard", which turns out to be her. She sees the Vespers, and she tells Madeleine that Olivia had hoped that she would never meet the Vespers, and they were lucky they avoided them for 19 years and tells Madeleine that the Vespers dosen't know she exists. She tells Madeleine to flee and  to keep her promise, and then she runs inside the building they here hiding in (O. Babbit and Daughter Apothecary) to protect the remains of Gideon's research from Damien's hands. She then presumably dies in a fire the Vespers lit, after she refused to open the door at Damien Vesper's men command. However, entries in her diary in Into the Gauntlet suggest that she survived the fire, as Madeline told her of her other children's deaths. After her death, it was revealed that she made Madeleine promise:

  1. Keep the ring safe
  2. Never let anyone abuse the power of the 39 Clues.
  3. Unite the Cahills when time is right.

Nowhere to Run[]

Olivia's birthplace, Bhaile Anois, is visited by Amy and Dan. Here they find a book given to Madeleine Cahill, given by Olivia, containing the Serum Antidote. It is also revealed that Leonardo da Vinci was her teacher.




Olivia in the eyes of her husband was beautiful, long hair, curly and black as midnight, with piercing green eyes.



She does not appear online.


She appears on the back of Card 111: Anak Krakatau.