T
- St. Tarasius
- St. Tarkin
- St. Tarsicius
- St. Tassach
- St. Teilo
- St. Teresa of Jesus (Teresa of Avila)
- St. Ternan
- St. Thecla
- St. Theodore of Amasea
- St. Theodotus of Ancyra
- St. Theophanes
- St. Thomas Aquinas
- St. Thomas Becket
- St. Thomas Christians
- St. Thomas Garnet
- St. Thomas More
- St. Thomas of Hereford
- St. Thomas of Villanova
- St. Thomas the Apostle
- St. Tigris
- St. Toribio Alfonso Mogrovejo
- St. Trudo
- St. Trudpert
- St. Tychicus
- Tabae (Caria)
- Tabasco (Mexico)
- Tabbora
- Tabernacle
- Tabernacle
- Tabernacle Societies
- Tabernacle Society
- Tacana Indians
- Tacapae
- Tadama
- Tadeusz Kosciuszko
- Taenarum (Greece)
- Taensa Indians
- Tahiti
- Tait Indians
- Takkali
- Talmud
- Tamanac Indians
- Tamassus (Cyprus)
- Tamaulipas
- Tametsi
- Tanagra (Hellas)
- Tancred, Prince of Antioch
- Tanis
- Tantum Ergo
- Taoism
- Taos Pueblo
- Tapestry
- Taranto
- Tarapaca
- Tarazona
- Tarbes
- Tarentaise
- Targum
- Tarnow
- Tarragona
- Tarsus
- Tatian
- Taubate
- Tavistock Abbey
- Tavium
- Taxa Innocentiana
- Te Deum
- Te Lucis Ante Terminum
- Teaching of Moses Maimonides
- Teaching of St. Augustine of Hippo
- Tegernsee
- Tehuantepec
- Teleology
- Telepathy
- Telese
- Telesphorus of Cosenza
- Telmessus
- Temiskaming
- Temnus
- Temperance
- Temperance Movements
- Temple
- Temple of Jerusalem
- Temptation
- Temptation of Christ
- Tenebrae
- Tenebrae Hearse
- Tenedos
- Teneriffe
- Tennessee
- Tentyris
- Teofilo Folengo
- Teos
- Tepic
- Tepl
- Teramo
- Terce
- Terence Albert O'Brien
- Terenuthis
- Teresa Lalor
- Termessus
- Termoli
- Terracina, Sezze, and Piperno
- Tertiaries
- Tertullian
- Teruel
- Testem Benevolentiae
- Teuchira
- Teutonic Order
- Tewdrig
- Texas
- Thabraca
- Thacia Montana
- Thaddeus Amat
- Thaenae
- Thagaste
- Thagora
- Thangmar
- Thanksgiving Day
- Thapsus
- Thasos
- Thaumaci
- The Tell El-Amarna Tablets
- The Ten Commandments
- The Ten Thousand Martyrs
- The Theatre
- The Thirty Years War
- The True Cross
- The Twelve Apostles of Erin
- Theatines
- Thebaid
- Thebes (Achaia Secunda)
- Thebes (Thebais Secunda)
- Theft
- Thegan
- Thelepte
- Themiscyra
- Themisonium
- Thennesus
- Theobald
- Theobald Mathew
- Theobald Stapleton
- Theocracy
- Theodat-Gabriel Sagard
- Theodicy
- Theodor Granderath
- Theodor Schwann
- Theodore Abucara
- Theodore Augustine Mann
- Theodore Balsamon
- Theodore Beschefer
- Theodore Coelde
- Theodore J. van Den Broek
- Theodore James Ryken
- Theodore O'Hara
- Theodore of Gaza
- Theodore of Mopsuestia
- Theodore of Studium
- Theodore William Achtermann
- Theodore, Archbishop of Canterbury
- Theodore, Count von Scherer-Boccard
- Theodoret
- Theodoric (Thierry) of Chartres
- Theodoric the Great
- Theodoric Vrie
- Theodorich Canisius
- Theodorus Lector
- Theodosiopolis
- Theodosius Florentini
- Theodosius I
- Theodulf
- Theological Aspects of the Avesta
- Theological Censures
- Theological Definition
- Theonas
- Theophanes Kerameus
- Theophilanthropists
- Theophile Raynaud
- Theophile-Jules Pelouze
- Theophile-Louis-Henri-Wyart
- Theophilus
- Theophilus
- Theophraste Renaudot
- Theophrastus Paracelsus
- Theosophy
- Thera
- Thermae Basilicae
- Thermopylae
- Thessalonica
- Theveste
- Thibaris
- Thibaut de Champagne
- Thierry of Freiburg
- Thignica
- Third and Fourth Books of Kings
- Third Council of Constantinople
- Third Lateran Council
- Third Orders
- Thmuis
- Thomas a Jesu
- Thomas a Kempis
- Thomas Abington
- Thomas and Arthur Marshall
- Thomas Anderton
- Thomas Andrew Becker
- Thomas Arthur
- Thomas Arundel
- Thomas Ashby
- Thomas Augustine Arne
- Thomas Augustine Hendrick
- Thomas Bailey
- Thomas Baily
- Thomas Bakocz
- Thomas Bouquillon
- Thomas Bourchier
- Thomas Bracken
- Thomas Burke
- Thomas Canon Flanagan
- Thomas Cardinal Wolsey
- Thomas Carve
- Thomas Ceva
- Thomas Chisholm Anstey
- Thomas Codrington
- Thomas Conecte
- Thomas d'Arcy McGee
- Thomas de Lemos
- Thomas de Vallgornera
- Thomas Dease
- Thomas Dempster
- Thomas Dongan
- Thomas Dorman
- Thomas Dwight
- Thomas Ebendorfer
- Thomas Edward Bridgett
- Thomas Ewing
- Thomas Eyre
- Thomas Falkner
- Thomas Fitz-Simons
- Thomas Fitzherbert
- Thomas Fleming
- Thomas Francis Meagher
- Thomas Godden
- Thomas Goldwell
- Thomas Grant
- Thomas Griffiths
- Thomas Harding
- Thomas Hussey
- Thomas Ignatius Maria Forster
- Thomas Joseph Lamy
- Thomas Kilby Smith
- Thomas Lewis Brittain
- Thomas Linacre
- Thomas Louis Green
- Thomas Malvenda
- Thomas Maria Mamachi
- Thomas Messingham
- Thomas Moore
- Thomas Morton Harper
- Thomas Murner
- Thomas Netter
- Thomas Nicholas Burke
- Thomas O'Hagan
- Thomas O'Herlahy
- Thomas Occleve
- Thomas of Beckington
- Thomas of Bradwardine
- Thomas of Cantimpre
- Thomas of Celano
- Thomas of Dover
- Thomas of Eccleston
- Thomas of Jesus
- Thomas of Jorz
- Thomas of Strasburg
- Thomas Percy Plowden
- Thomas Plowden
- Thomas Pounde
- Thomas Preston
- Thomas Rolph
- Thomas Sanchez
- Thomas Scott Preston
- Thomas Sedgwick
- Thomas Slythurst
- Thomas Somerset
- Thomas Stapleton
- Thomas Stephen Buston
- Thomas Stephens
- Thomas Talbot
- Thomas Tallis
- Thomas Tamburini
- Thomas Vane
- Thomas Vavasour
- Thomas Vincent Faustus Sadler
- Thomas Walsh
- Thomas Walsingham
- Thomas Ward
- Thomas White
- Thomas William Allies
- Thomas William Croke
- Thomas Wingham
- Thomas Wood
- Thomas Worthington
- Thomas-Marie-Joseph Gousset
- Thomism
- Thompson River Indians
- Thorney Abbey
- Three Chapters
- Three Rivers (Quebec)
- Throne
- Thuburbo Minus
- Thugga
- Thundering Legion
- Thuringia
- Thyatira
- Thynias
- Thyrsus Gonzalez de Santalla
- Tiara
- Tiberias
- Tiberiopolis
- Tiberius
- Tibet
- Ticelia
- Ticonius
- Ticuna Indians
- Tiepolo
- Tighernach O'Braein
- Tilman Pesch
- Timbrias
- Time
- Timoleon Cheminais de Montaigu
- Timothy Warren Anglin
- Timucua Indians
- Tingis
- Tinos and Mykonos
- Tintern Abbey
- Tipasa
- Tiraspol
- Tiro Prosper of Aquitaine
- Tithes
- Titian
- Titiopolis
- Titular Archdiocese of Hierapolis
- Titular See of Philadelphia
- Titular See of Phocaea
- Titulus
- Titus
- Titus, Bishop of Bostra
- Tius
- Tivoli
- Tlaxcala
- Tlos
- To the Knights of Columbus
- Toba Indians
- Tobias Lohner
- Todi
- Tokio (Tokyo)
- Toledo (Ohio)
- Toledo (Spain)
- Tomas Camara y Castro
- Tomas de Torquemada
- Tomb
- Tomb of St. Peter
- Tomb of the Blessed Virgin Mary
- Tomi
- Tommasina Vernazza
- Tommaso Badia
- Tommaso Campanella
- Tommaso de Vio Gaetani Cajetan
- Tommaso Maria Zigliara
- Tommasso Giordani
- Tonica Indians
- Tonkawa Indians
- Tonsure
- Torah
- Toribio de Benavente Motolinia
- Torlogh O'Carolan
- Torone
- Toronto
- Torquato Tasso
- Tortona
- Tortosa
- Tosephta
- Totemism
- Totonac Indians
- Toulouse
- Tournai
- Tours
- Tower of Babel
- Tradition and Living Magisterium
- Traditionalism
- Traducianism
- Trajan
- Trajanopolis
- Trajanopolis
- Tralles
- Trani and Barletta
- Transcendentalism
- Transept
- Transfiguration
- Transvaal
- Transylvania
- Trapani
- Trapezopolis
- Trappists
- Trebizond
- Trebnitz
- Tremithus
- Trent
- Trenton
- Treviso
- Tricarico
- Tricca
- Trichinopoly
- Trichur
- Tricomia
- Triduum
- Trier
- Triest-Capo d'Istria
- Trincomalee
- Trinity College
- Trinity Sunday
- Triple-Candlestick
- Tripolis
- Tritheists
- Trivento
- Troas
- Trocmades
- Trope
- Troyes
- Truce of God
- Trudpert Neugart
- Trujillo
- Trustee System
- Trusts and Bequests
- Truth
- Tryphon, Respicius, and Nympha
- Tschiderer Zu Gleifheim
- Tuam
- Tubunae
- Tucson
- Tucuman
- Tudela
- Tuguegarao
- Tulancingo
- Tulle
- Tunic
- Tunis
- Tunja
- Tunkers
- Turin
- Turkestan
- Turkish Empire
- Turpin
- Tuscany
- Tuy
- Twiketal of Croyland
- Tyana
- Tynemouth Priory
- Types in Scripture
- Tyrannicide
- Tyre