In case anyone has run across this anywhere, you can read a good counter-argument on Sean's Faith website.
An excerpt of his research:
Cardinal Hosius and that infamous "statement": Is it genuine?
The statement reads as follows:
"Were it not that the baptists have been grievously tormented and cut off with the knife during the past twelve hundred years, they would swarm in greater number than all the Reformers." (Hosius, Letters, Apud Opera, pp. 112, 113.)" Quoted in the "Trail of Blood" by J. Carroll.
Does this statement exist in his complete works? No.
The complete works of Cardinal Stanislaus Hosius were published in two volumes in 1584 in Cologne, under the title "Opera Omnia". The complete title reads as follows:
D.STANISLAI HOSII, S R E CARDINALIS, MAIORIS POENITENTIARII; ET EPISCOPI VARMIENSIS
"Opera Omnia in Duos divisa tomos, quorum primus ab ipso auctore plurimus subinde in locis, integris & dimidijs paginis sic auctus & recognitus, ut novum opus fere censeri possit. Secundum autem totus novus, nuncque primus typis excusus."
Apud Maternum Cholinum
Anno M. D. L XXXIIII
The purported statement is nowhere to be found in the letters of Cardinal Hosius
- There is no section titled "Apud Opera" among Hosius� complete works. And there is no letter of that name. So the reference "Letters, Apud Opera" is apparently meaningless. Similarly, I could find no publication of his with this title.
- I decided to check all of Cardinal Hosius� letters for references to the Anabaptists. The section in his "Opera Omnia" entitled "Liber Epistelarum" contains all of Cardinal Hosius� letters, 277 in total, written in Latin. I have read through all of these letters, and in only 12 of them (letters XXVIII, XLI, XLIII, CV, CXVI, CXXVIII, CXXIX, CXXXIV, CL, CLVII, CLVIII, and CLX) is there any mention of the Anabaptists. In none of them is to be found the statement cited at the top. To all intents and purposes, this statement appears to be a fake.
- Nowhere in the letters of Hosius are the "reformers" referred to as such. Rather, they are referred to as "Lutherani", "Calvinisti", "Zuingliani" and, especially in his other works, "haeretici". The purported statement of Hosius uses language he never uses in his "Opera omnia", and so its authenticity must be called into question.
- The citation by various Baptist websites of two completely different purported statements by Cardian Hosuis, both given the same page reference, adds to the doubt about the genuineness of either. (The second purported statement is quoted in Note 1 below). The said statements are purported to be found on pages 112, 113 of "Apud Opera". However, only one statement can be found crossing over from page 112 to 113. How can you get two different statements, both starting on page 112 and both ending on page 113? (The only possibility would be if one statement were embedded in the other, but that is clearly not the case here.)