Viscounty of Castellbò and Catharism Historical milestone · Montferrer i Castellbò, Alt Urgell, Lleida Image of Montferrer i Castellbò, not of the place itself. The viscounty was a focus of Cathar sympathies in the thirteenth century and the viscount Arnau de Castellbò and his daughter Ermessenda were accused of heresy. The marriage of Ermessenda to Roger Bernat II of Foix, in 1208, brought the rights over Andorra to the house of Foix. siglo XIII Photo: Ermengol Patalín (CC BY-SA 3.0) What to see and do in Montferrer i Castellbò