CALIXTINES, the followers of George Calixtus, a learned Lutheran divine, and professor at Helmstadt, who died in 1656. Calixtus opposed the opinions of St Augustin on predestination, grace, and free will, and endeavoured to form a union among the various members of the Romish, Lutheran, and Reformed churches; or at least to unite them in the bonds of mutual forbearance and charity.