Saint Silverius, son of St. Hormisdas, was only a subdeacon when he was interjected into the Bishopric of the Church by the Ostrogothic king, Theoldehad in 536. He was eventually and reluctantly accepted by the clergy of Rome.
Empress Theodora attempted to insert two monophysite -- those that believe Jesus had only one nature, not two (human and divine) -- priests as Patriarchs in the east. Silverius refused politely, but she was a vile and unscupulous woman who did not take no as an answer from anyone.
The Empress' general, Vitiges, sacked suburban Rome, and at that point Pope Silverius allowed Vitiges' rival, Belasarius, to enter and save Rome. With this, Theodora tried in vain to forge a letter implicating the Pope as a treasoner. This failed, and she had him kidnapped and taken to Patara in Asia minor.
In the mean time, the Empress tried to force her choice as Pope -- Vigilius, on Rome. The Emperor Justinian found out the circumstances, and decided to let the saint go, only to be persuaded otherwise, and Silverius was then taken to the island of Palmarola, also known as Pontus, off Naples.
There on that island Pope Saint Silverius died from his sufferings and treatment, and is venerated as a martyr. Vigilius was somehow regularized as the next Pope. After this, he turned from his heretical ways of Monophysism to become a champion of orthodoxy.