Early Christian architecture of historic Europe, so called because it was peculiar to the Latin Church, and was developed among the Latin races of Italy.
It may be said to have first appeared during the reign of Constantine the Great, 306-337, and to have held its position until the 8th century.
The churches constructed during the period were mostly of the basilican form, T-shaped rather than cruciform, and characterized by architectural plainness.
The best examples are Saint John Lateran, Saint Peter's, and Saint Paul Without The Walls.
All three were destroyed, and only the latter was rebuilt in the original form.
New Catholic Dictionary