Issued 19 April 1666 by Pope Alexander VII, the apostolic constitution In suprema was a response to an appeal by Claude Vaussin, Abbot of Citeaux, for help in dealing with divisions in the Order over the question of reform. The Pope recognized the need for a general reform and invited the Order to reflect on how to implement it.

And so that in the future everyone everywhere will live under a single rule, with the same charity and with identical customs, and so that all those of either sex belonging to the Order know what constitutes a stricter Observance (apart from the abstinence of meat) a short, clear compilation and resumé will be made of all the apostolic constitutions and statutes which have not been repealed by contrary usage or for some other reason (…)