In his book Portrait of Calvin, T. H. L. Parker tells this story about how the possibility of unity between the reformed churches was shipwrecked on the rocks of astrology:
Near the end of Calvin’s life Bullinger wrote to Cranmer urging that England should not send a delegate to the Council of Trent.
He replied that the King had never thought of doing so, but added that he had recommended that “His Majesty grant his assistance, that in England, or elsewhere, there might be convoked a synod of the most learned and excellent persons, in which provision might be made for the purity of the Church doctrine, and especially for an agreement upon the sacramentarian controversy.”
On the same day he wrote in similar terms to Calvin, who replied that he would cross ten seas to attend such a council. But when Cranmer invited Melanchthon, the scheme shipwrecked, for his fear of the long journey was augmented when he consulted the stars, of which he was a hopeful student.
The Reformed Churches stayed apart, and Calvin’s desire has yet to be fulfilled: “Would that the union between all Christ’s Churches upon earth were such, that the angels in heaven might join their song of praise.” (121-122)