Christian Classics Ethereal Library:
Extremely helpful source of primary texts in church history, Christian spirituality, Christian music, and more

Christian History:

Lectio Divina: Christian Spiritual Authors:
Index page of sources for spiritual reading; many good primary texts in early Christian theology and spirituality.

The Holy See
Official Website of the Holy See: papal and curial documents in different languages.

The Ecole Initiative
"A Hypertext Encyclopedia of Early Church History" (and primary texts)

Christus Rex
Christian Art, The Holy Land, Papal Documents

New Advent
Patristic Texts, The 1908 Catholic Encyclopedia, Hagiography

Ignatian Spirituality
The Spiritual Exercises, St. Ignatius, Ignatian spirituality, and more.

Late Medieval Hagiography
The Golden Legend, published 1483

Jordan Aumann (articles and complete text of Spiritual Theology and Christian Spirituality in the Catholic Tradition

 Internet Archive: (Many, many out-of-print texts and other media)


....x....   .