The following observation of Bruce Gordon is worthy of careful consideration. Gordon was previously at St Andrews, Scotland, and is now at Yale. This comment of his is typical of his perceptive scholarship:
“Both men (ie Calvin and Bullinger) understood the need for unity, but they also understood how deep the divisions within the Protestant world ran, and it is a measure of their desire for mutual support that they could put their names to a document on the Lord’s Supper, the Consensus Tigurinus of 1549. Too much has been made of this agreement, which was, for the most part, a practical arrangement which suited both men. It was a partnership which worked well: Bullinger supported Calvin both openly and tacitly, agreeing not to disagree in public, and together they formed a common front against Lutheran opponents, such as Joichim Westphal, who wrote against the Swiss in the mid-1550’s” (Architect of Reformation, p20).
In an earlier post I suggested that it was Calvin who was more keen to have such a jointly signed agreement.