In his elegant study of Reformation commemorations (Remembering the Reformation), Thomas Albert Howard notes that the first centenary of the 95 Theses started out as an ecumenical effort. Elector Friedrich V of the Rhineland Palatinate hoped to “reduce tensions between Lutheran and Calvinist members” of the Protestant Union. Calvinists were not recognized within the HolyRoman Empire, and they “desired to build bridges to their Protestant co-religionists, differences and acrimony notwithstanding” (13). A joint resolution of April 1617 “affirmed that during the celebrations all bitterness and personal attacks among Protestants should be suspended and a general thanksgiving offered to God for the recovery of maintenance of the true evangelical faith some 100 years before” (14).
Not everyone was pleased with the prospect of reduced tension. In Wittenberg, scholars “seized upon the moment to assert their own custodial leadership of Lutheran orthodoxy and rally together the ‘pure’ territories,” those that had accepted the Formula of Concord of 1577. Thus, “from the outset, inter-Protestant irenicism was not the goal in Wittenberg. Quite the opposite: the then circulating catch-phrase ‘God’s word and Luther’s writings are poison to Papists and Calvinists alike' better captures he mood” (14).
A century later, even that modest effort at union was forgotten. Calvinists didn't have the same political interest in linking with Lutherans, since they had been recognized by the Peace of Westphalia. As a result, the bicentennial was “a more confessional Lutheran affair than 1617” with “the idea of a unified Protestantism being largely a thing of the past” (24-25).