- Theoricae novae planetarum (Peurbach, Georg von)2
- Therapeutics8
- Theravāda Buddhism1
- Theravāda Buddhism--Doctrines1
- Theseus, King of Athens1
- Thilla, Berto1
- Third Order Regular of St. Francis2
- Third Order Secular of St. Francis1
- Third orders1
- Thirteenth century564
- Thirty Years' War (1618-1648)1
- Thomas de Grinham1
- Thomas, Apostle, Saint, active 1st century1
- Thomas, Aquinas, Saint, 1225?-12744
- Thomas, à Becket, Saint, 1118?-11701
- Thomists1
- Three Weeks (Jewish mourning custom)6
- Throat--Diseases1
- Thumb indexes3
- Thunder--Religious aspects1