Tractatulus Devotus (A Short Devotional Treatise)
A verified public-domain excerpt for this text is still being set. The folio is catalogued and linked below; an original Sub Rosa rendering will follow.
What it is
Florens Radewijns (c. 1350–1400), co-founder of the Brethren of the Common Life and Groote's principal disciple, wrote this short practical manual — full scholarly title Tractatus devotus de extirpatione vitiorum — for the laypeople and young scholars in his care at Deventer. It condenses the entire Devotio Moderna formation programme into one brief guide: methodical prayer, examination of conscience, accumulation of spiritual maxims in personal notebooks (rapiaria), and the gradual cultivation of virtue through repetition and self-awareness. Thomas à Kempis was shaped by Radewijns' formation tradition, which found its highest literary expression in the Imitation of Christ; the Tractatulus is therefore the proximate source document for that tradition.
Why it still matters
The Tractatulus Devotus is short enough to read in a single sitting and practical enough to begin using the same day; its core discipline of keeping a personal rapiarium — a notebook of spiritual maxims gathered from reading — is a formation practice any Christian can adopt immediately.
Kept alongside
Soliloquium Animae (Soliloquy of the Soul)
One of Kempis's most characteristic minor works, the Soliloquium Animae is a sustained interior dialogue between the soul and God organized around themes of divine love, humility, and perseverance in the life of grace. Published as part of his Opera omnia, it was particularly prized in Windesheim houses as a companion to the Imitation of Christ, and an early English translation survives at the Folger Shakespeare Library. It shares with the Imitation the same intimate, second-person address to Christ but has a more lyrical, prayer-like structure that renders it immediately usable as vocal prayer.
De Spiritualibus Ascensionibus (On the Spiritual Ascents)
Gerard Zerbolt of Zutphen (1367–1398), librarian of the Deventer house of the Brethren of the Common Life, wrote this 70-chapter handbook of interior reform describing the soul's ascent from sin back toward paradisical innocence through methodical self-examination, affective meditation, and progressive virtue. Organized around the scriptural motto from Psalm 83:6 — 'He has set ascents in his heart' — it was the most widely circulated devotional work from Devotio Moderna scriptoria and was probably present in nearly every house of the movement. First printed by R. Pafraet in Deventer c. 1483–85 and reprinted into the sixteenth century, its method of structured imaginative meditation on Scripture anticipates the Ignatian Spiritual Exercises by more than a century.
Prayers and Meditations on the Life of Christ
A collection of meditations and prayers on the Incarnation, Passion, Resurrection, and Ascension of Christ, forming a practical companion to the Imitation of Christ and the wider Vita Christi tradition. Where the Imitation focuses on interior dispositions, this work provides concrete meditative content keyed to Gospel events, functioning as a guide for lectio divina-style prayer through the mysteries of the Lord's life. Circulated in Windesheim and Augustinian communities as a formation text for novices, it was first translated into English by Henry Lee in 1762 and remains available in digitized editions.