First Edition. Cassander sought common ground in the tenets and teachings of the early church to foster the reunification of Catholics and Protestants. Here he takes up the Eucharist, emphasizing Christ's sacrifice for all believers and arguing that both Protestants and Catholics receive the sacrament's spiritual benefits. But he stopped short of asserting the veracity of transubstantiation, which rendered him suspect to Catholic authorities and ultimately landed this on the Index of Prohibited Books. Historian and bibliophile, JACQUES-AUGUSTE DE THOU OWNED, READ, AND COMMENTED FAVORABLY ON CASSANDER. Shortly before his death, de Thou (1553-1617) asked for Cassander's manuscripts to be sent from Leiden to him in Paris. Jean-Jacques Charron, marquis de Ménars (1643-1718), purchased de Thou's library. In 1706, Ménars sold his collection to Cardinal Armand de Rohan-Soubise (1674-1749), who added his shelfmark to the front pastedown. However, the cardinal apparently disposed of this copy, which entered the Colbert family library (title inscription, dispersed in 1728). No example in American collections. In nice condition, 19th-century blue stamp of hh, French bookticket on rear pastedown. Catalogus bibliothecæ thuanæ (1704) 82; Bibliotheca Colbertina (1728) 13336; VD 16 C 1402 Contemporary gilt-ruled vellum with the bachelor arms of Jacques-Auguste de Thou on the panels and his small cipher in the gilt-ruled spine compartments (O-H-R 216, fers 2 & 3 variant), gilt-lettered spine title, all edges gilt, four purple silk ties (replacements)