Antipope Adalbert

https://en.wikipedia.org/wiki/Antipope_Adalbert

Adalbert (or Albert) was elected pope of the Catholic Church in February 1101 and served for 105 days. He was a candidate of the Roman party opposed to Pope Paschal II and is regarded today as an antipope. Prior to his election he was created a cardinal by the antipope Clement III. He was captured by partisans of Paschal II and forced to live out his days as a monk.