- Theology--Study and teaching--Catholic Church1
- Theoricae novae planetarum (Peurbach, Georg von)1
- Therapeutics3
- Thilla, Berto1
- Third Order Secular of St. Francis1
- Third orders1
- Thirteenth century149
- Thomas, Apostle, Saint, active 1st century1
- Thomas, Aquinas, Saint, 1225?-12741
- Three Weeks (Jewish mourning custom)2
- Throat--Diseases1
- Thumb indexes2
- Thyestes, King of Olympia and Mycenae (Mythological character)1
- Ties1
- Tikkun ḥaẓot4
- Time measurements4
- Time--Religious aspects--Islam1
- Timekeeping9
- Timur, 1336-14052
- Timurids1