Roman Catholic and Orthodox churches: General Biographies
- Frederic Baraga
- Fulton J. Sheen
- Gerard Groote
- Girolamo Savonarola
- Gottfried Wilhelm Leibniz
- Gratian
- Hans Kung
- Heloise
- Henry Edward Manning
- Isaac Thomas Hecker
- Jacobus da Varagine
- Jacques Benigne Bossuet
- Jean Baptiste Henri Lacordaire
- Jean Baptiste Lamy
- Jean Mabillon
- Joachim of Fiore
- Johann Maier von Eck
- Johann Tetzel
- Johannes Tauler
- John Ball