His cultural background, embracing the Greek and Roman worlds, afforded him a unique view of the age-old question of union to heal the Great Schism.

Thus in 1651, when he published the first printed edition of the works of George Acropolites, the 13th century emissary of the Byzantine Emperor who acknowledged the supremacy of the Roman pontiff and thus had become something of a celebrity, at least in the West, the Latin essay that formed the preface to this volume, De Georgiis eorumque Scriptis, gained fame itself as a learned plea for the commonalities between the two churches.

So he argued in his contribution to the mid-17th century Uniate pamphlet De Ecclesiae occidentalis atque orientalis perpetua consensione libri tres ("The Western and Eastern Churches in perpetual Agreement, in Three Books") (1648).

In his later years he collected Greek and Syrian manuscripts to add to the late Pope Gregory XV's Eastern Library at the Vatican.

437), where they are divided into four classes: His manuscripts (about 150 volumes) and his voluminous scholarly correspondence are held in the Biblioteca Vallicelliana (referred to by some sources as the "Library of the Oratorians") in Rome.

Outside scholarly circles Allatius is perhaps best known today for his De Praeputio Domini Nostri Jesu Christi Diatriba (Discourse on the Foreskin of Our Lord Jesus Christ), a minor essay mentioned in Fabricius's Bibliotheca Graeca (xiv.