ACONCIO, GIACOMO (1492-1566?), pioneer of religious toleration, was one of the Italians, like Peter Martyr and Ber nardino Ochino, who repudiated Roman Catholic doctrine and ultimately found refuge in England, where he worked as an engineer on various public works. Before reaching England he had published a treatise on the methods of investigation, De Methodo, hoc est, de recte investigandarum tradendarumque Scientiarum ratione (1558) ; and his critical spirit placed him outside all the recognized religious societies of his time.
On his arrival in London he had joined the Dutch Reformed Church in Austin Friars, but he was "infected with Anabaptis tical and Arian opinions" and was excluded from the sacrament by Grindal, bishop of London. The real nature of his heterodoxy is in his Stratagemata Satanae (1565). The "stratagems of Satan" are the dogmatic creeds which rent the Christian church. Aconcio sought to reduce dogma to a minimum in the hope of finding a common denominator for the various creeds.