The fact that in the year: 1634 the English Benedictine priest, Leander Jones, came to England on some sort of special mission connected with the Roman and Anglican Churches is comparatively widely known, and a number of writers have referred to it and even given some account of the mission, quoting to a greater or lesser extent from documents that Leander wrote in the course of it. There is not, however, complete agreement among these writers as to either the origin or the exact nature of the work that he was undertaking, and the accounts of it have all been incomplete and incidental. The purpose of this article is to attempt to discover from his own writings what in fact he was trying to do, and to trace, as far as may be, in the ensuing correspondence the reception which his efforts met with in Rome.