I ran across this inspiring account while researching for a class project:

"One of the most notable and renowned cases of solitary confinement comes from the story of pastor Richard Wurmbrand who ranks fifth among the greatest Romanians of all time according to the Mari Români poll. In 1948, Wurmbrand was … sentenced to solitary confinement for his involvement in underground churches. Wurmbrand endured years of solitary torture, both mentally and physically all the while composing hundreds of sermons, delivered nightly to an unseen (fictional) congregation. He later committed them to memory by summarizing them in rhymes.
Pastor Wurmbrand was released in 1956, after eight and a half years, and, although warned not to preach, resumed his work in the underground church. He was arrested again in 1959, and sentenced to 25 years. During his imprisonment, he was beaten and tortured."


This was spliced together from two seperate wikipedia articles on solitary confinement and Richard Wurmbrand, respectively. Since I assume that correct citation is not that important for wikipedia, I won't make the effort to correctly cite the sources.