On 20 December 1463 Hupert von Heinsberg, a Hospitaller priest, made a foundation for the celebration of mass in his commandery’s chapel at Cologne. The foundation was probably linked to another – that of a fraternity in honour of St John the Baptist. Mass would be celebrated at an altar to be erected for the purpose. 1 The letter of confirmation which the baiulus of Mallorca, John de Cardona, as lieutenant of the grand master and visitor for Germany, had issued on 30 June 1463, provides evidence of this connection. 2 But the real date of the foundation charter is not known with any certainty. The day and month cannot be traced in the original. They can be identified in a copy found at the commandery’s copiarium. Assuming that the foundation was genuine and that both the copyist and the brothers of St John are to be believed, it should also be assumed that discussions and negotiations must have preceeded the actual foundation of the fraternity, the altar, and the celebration of mass earlier than 20 December. Hupert von Heinsberg’s project could not have been realized before it had been approved by his superior at the commandery at Cologne.