Among the many juicy bits of history packed into Philip Benedictâ€™s Christâ€™s Churches Purely Reformed comes the item about the Ottoman insurgence into the Holy Roman Empire. Turns out the influx of Muslims into formerly Roman Catholic territories was a boon to the Reformed faith, especially in Hungary which gave us the Magyar Reformed Church.
Not only was the church largely decapitated in the central portions of the kingdom (i.e., Hungary), much of the parish clergy fled before the Ottoman onslaught, leaving nearly four-fifths of the localities in Ottoman-controlled regions without parish priests. Finally, the new rulers of the portions of the kingdom had neither the liberty nor the inclination to pursue the campaign against heresy. Ferdinand (Roman Catholic and from the Habsburg dynasty) was so busy with his military campaigns that he had little time to concentrate on the problem of heresy within his lands. Furthermore, he depended heavily on Protestant support within the empire for tax revenue to help fight the Ottomans, which prompted him to favor negotiation over repression in dealing with the problem. The Ottoman authorities looked for religious leaders who might cooperate with them as they strove to organize their control over their recently conquered territories and stem the flight of the population from the region. They were thus prepared to give evangelical preachers a free hand to proselytize so long as they respected Ottoman authority.
. . . . In the Ottoman-controlled regions, wandering preachers had a free hand. Mihaly Sztairai (d. 1575), a Paduan-educated ex-Franciscan who was the chief evangelist of the western portion of Ottoman Hungary, reported to a Viennese correspondent in 1551 that he had been able to preaching throughout the region for the previous seven years. In the process, he claimed, he and his fellows had founded some 120 congregations. (pp. 274, 275)
Now thatâ€™s church growth.