The Houtborg triplets were not in fact triplets, but a set of twins and a third child: Fiona, Amavet, and Adela.
The three had been born at roughly the same time at Fort Houtborg, with the captured Temerian queen, Riannon, having given birth to twins while the rebellion's leader, Falka, had a single child. Despite Riannon having gone insane during her imprisonment, Falka placed her own child in Riannon's care while she continued her rebellion. When the rebellion was quelled, Falka was burned at the stake and King Goidemar reunited with his wife, albeit with three children.
As Riannon could not tell the children apart, she never knew which two were in fact her own, even after she recovered from her insanity. Goidemar therefore hired several mages to determine which of the children were his. The mages did succeed, figuring out it was Adela, but decided not to reveal their findings as that would have meant the execution of a two year old child. So they instead noted to the king they were not able to immediately determine which was Falka's child and would need some time. For his part, Goidemar never followed up for further information as he and his wife were happy raising the three children and, as a result, the royal couple raised all three as their own.[1]
Notes
- Many years later, Fenn would suggest that Fiona was actually Falka's daughter, not Adela. However, this is conflicting information, as they were referring to a prophecy that suggested one of Falka's blood would destroy the old world, with the implication being that Ciri's child would bring that prophecy to fruition.[2]