In 1675, Molinos published a book entitled "Il Guida Spirituale," to which were subjoined recommendatory letters from several great personages. One of these was by the archbishop of Reggio; a second by the general of the Franciscans; and a third by father Martin de Esparsa, a Jesuit, who had been divinity-professor both at Salamanca and Rome.
No sooner was the book published, than it was greatly read, and highly esteemed, both in Italy and Spain; and this so raised the reputation of the author, that his acquaintance was coveted by the most respectable characters. Letters were written to him from numbers of people, so that a correspondence was settled between him, and those who approved of his method, in different parts of Europe. Some secular priests, both at Rome and Naples, declared themselves openly for it, and consulted him, as a sort of oracle, on many occasions. But those who attached themselves to him with the greatest sincerity, were some of the fathers of the Oratory; in particular three of the most eminent, namely, Caloredi, Ciceri, and Petrucci. Many of the cardinals also courted his acquaintance, and thought themselves happy in being reckoned among the number of his friends. The most distinguished of them was the cardinal d'Estrees, a man of very great learning, who so highly approved of Molinos' maxims, that he entered into a close connexion with him. They conversed together daily, and notwithstanding the distrust a Spaniard has naturally of a Frenchman, yet Molinos, who was sincere in his principles, opened his mind without reserve to the cardinal; and by this means a correspondence was settled between Molinos and some distinguished characters in France.
Whilst Molinos was thus labouring to propagate his religious mode, father Petrucci wrote several treatises relative to a contemplative life; but he mixed in them so many rules for the devotions of the Romish church, as mitigated that censure he might have otherwise incurred. They were written chiefly for the use of the nuns, and therefore the sense was expressed in the most easy and familiar style.
Molinos had now acquired such reputation, that the Jesuits and Dominicans began to be greatly alarmed, and determined to put a stop to the progress of this method. To do this, it was necessary to decry the author of it; and as heresy is an imputation that makes the strongest impression at Rome, Molinos and his followers were given out to be heretics. Books were also written by some of the Jesuits against Molinos and his method; but they were all answered with spirit by Molinos.