Having thus secured for themselves religious privileges, the Frankfort exiles by a circular letter invited their brethren in other continental cities to come and share the blessing with them. To this the English residents at Strasburg replied recommending certain persons as well qualified to fill the offices of superintendent or bishop, and pastors, but before receiving that communication the brethren at Frankfort had already chosen three persons, one of whom was Knox, to be their pastors, and to be invested with co-ordinate authority. The invitation was not specially attractive to Knox, both because he was loth to sacrifice the advantages for study which he was enjoying at Geneva, and because he feared the outbreak of such a {85} controversy as ultimately arose. But moved by what McCrie has styled "the powerful intercession of Calvin," he accepted the call and went to Frankfort about the end of October or the beginning of November. Before his arrival there, however, the harmony of the congregation had been disturbed by the reception of a letter from the English residents at Zurich, who declined to come to Frankfort unless they obtained security that the Church would use the Prayer-Book of King Edward VI., on the ground that the rejection or alteration of that form of service would give occasion for the charge against them of fickleness in their religion, and would be a virtual condemnation of those who at that very time were suffering persecution on its account. To this the members of the church at Frankfort replied that they had obtained permission to use their place of worship on the condition of their conforming as closely as possible to the French ritual; that there were some things in the English book which would give offence to the Protestants of the place whose hospitality they were enjoying; that certain ceremonies in that book had been occasion of scruple to conscientious persons at home; that they were very far indeed from pronouncing condemnation of those who had drawn up that book, since they themselves had altered many things; and that the sufferers in England were testifying for more important matters than rites of mere human appointment. This answer, while it somewhat abated the confidence of the friends at Zurich, did not {86} drive them from their purpose, for they instigated their brethren at Strasburg to make the same request both by letter and by deputation, and thus widened the area of the controversy.