Peter had chosen as temporary Guardian Exarch the forty-two-year-old Metropolitan of Ryazan, Stephen Yavorksy, a Ukrainian monk trained in the Jesuit-inspired Orthodox academy in Kiev, where the level of church scholarship and general culture was higher than among the purely Muscovite Orthodox clergy. As professor of theolgoy at the academy and a frequent orator in the city's great Santa Sophia Cathedral, Yavorsky made an impressive figure. His deep, sonorous voice, his dramatic gestures, his skillful blend of scholarship and anecdote moved his large audiences easily from laughter to tears. Peter had never heard such oratory in a Russian church, and whenever possible—at church ceremonies, public dedications or military triumphs—he asked that Yavorsky preach. But in giving office to Yavorsky, Peter did not equip him even temporarily with all the authority formerly held by the Patriarch. The actual administration of church properties, as well as the taxing of all inhabitants of ecclesiastical lands, was turned over to the new Monastery Office headed by Musin-Pushkin. Thereafter, most church income went directly into the state Treasury, which, in turn, paid the salaries of church officials.
Yavorsky was never really happy in his office. He was not ambitious, and soon he was looking back wistfully on the calmer, more reclusive life he had led in Kiev. In 1712, he begged Peter to release him from his assignment. "Where shall I go from your spirit and how shall I flee from your face?" he wrote despairingly to the Tsar. "I will not go to a foreign realm, for your power is given to you by God. In Moscow or in Ryazan—everywhere your sovereign power reigns over me. It is impossible to hide from it." Peter, having no one to replace him with, always refused Yavorsky's appeals until, with the passage of time, Yavorsky began to grow stronger in his office; he began to support his fellow churchmen in their confrontation with civilian authorities; he began to protest the extent to which church revenues were being diverted from religious purposes to support the army and the war. Even his sermons began to take a turn which Peter did not like: He preached against husbands who had persuaded their wives to enter a convent so that the husbands could remarry—a thrust whose most prominent target was obvious to all. In 1712, Yavorsky used the occasion of the Feast of St. Alexis to speak of the Tsarevich Alexis as "our only hope." Peter was not present, but a copy of the sermon was brought to him. He read it carefully, annotating it with his pen. Unwilling to make Yavorsky a martyr, he did not retaliate, but sent word to the churchman that he should not admonish in public before doing so in private. Yavorsky apologized, "writing with tears, not with ink," and remained in office, although for a while Peter forbade him to preach.
Thereafter, Peter found a new instrument with which to reform the church. This was another Ukrainian monk from Kiev, much younger than Yavorsky, more sophisticated, more practical and infinitely more forceful. Feofan Prokopovich was a modern eighteenth-century man who happened to be a cleric. He was an administrator, a reformer, a polemicist, even a propagandist, and he concurred completely in Peter's desire to modernize and secularize the Russian church. For a Russian churchman, Prokopovich was a man of extraordinary learning—he had read Erasmus, Luther, Descartes, Galileo, Kepler, Bacon, Machiavelli, Hobbes and Locke. An orphan in childhood, Prokopovich was educated by his uncle, a learned monk and rector of the academy in Kiev, and went on to Jesuit colleges in Poland and then to a special college in Rome. There, he studied theology, took Catholic orders and, in 1700 at the age of twenty-two, witnesses the coronation of Pope Clement XI. The effect of his three years in Rome, however, was to instill in Prokopovich a permanent dislike of the Papacy and the Roman church. Returning to the Kiev academy, he taught philosophy, rhetoric, poetics and literature, lecturing to his students in Latin. He pioneered in introducing arithmetic, geometry and physics into the curriculum. While still in his twenties, he wrote a five-act play in verse, dramatizing the theme of the bringing of Christianity to Russia in the tenth century by Vladimir, Prince of Kiev. In 1706, Peter visited Kiev and heard Prokopovich preach in Santa Sophia. In the crisis of 1708, when Mazeppa betrayed the Tsar in favor of Charles XII, Prokopovich quickly took Peter's side. Prince Golitsyn, Governor of Kiev, responded to Peter's question about the loyalty of the higher clergy in the city by saying, "All the monks avoid us. In all of Kiev I have found only one man, the prefect of the academy [Prokopovich], who is well disposed toward us." In 1709, following the Russian victory at Poltava, the Tsar returned to Kiev, where Prokovich welcomed him as "His Most Sacred Majesty, the Tsar of All the Russias" and preached a sermon filled with superlatives. In 1711, Prokopovich accompanied Peter on the disastrous campaign on the Pruth, and later that year, at the age of thirty-one, he was appointed rector of the Kiev academy. In 1716, the Tsar summoned him to St. Petersburg, and Prokopovich left Kiev, never to return.
Unlike Yavorsky, Prokopovich firmly supported Peter's attempts to subordinate the church to the state. Vockerodt, secretary to the Prussian minister Mardefelt, commented that he found in Prokopovich, apart from wide learning, "an ardent concern for the good of the country, even at the expense of the clergy's interests." Prokopovich's antagonism toward the "beards of the church" was further stimulated by their support of the Tsarevich Alexis, and on Palm Sunday, April 6, 1718, as the leaders of the church were being asked to judge the Tsarevich, Prokopovich thundered from the pulpit on the power and glory of the tsar and the holy duty of all subjects to obey the temporal power. "The supreme authority is established and armed with the sword of God, and to oppose it is a sin against God himself," he cried. He dealt harshly with the idea that the clergy was exempt from loyalty and service to the sovereign: "The clergy, like the army, the civil administration, doctors and artisans, is subject to the state. The clergy is another order of rank of the people and not a separate state." Naturally enough, the rest of the clergy accused Prokopovich of sycophancy, opportunism, hypocrisy and ambition. When Peter nominated him as Archbishop of Pskov and Narva, the Moscow clergy accused him of heretical Protestant leanings.
Yavorsky joined this attack until Peter asked for evidence; unable to document his charge, the Exarch was obliged to retract it.
As the war with Sweden drew to a close, Peter's thoughts turned toward a permanent structure for governing the church. Repeatedly and urgently, the bishops begged the Tsar to name a new patriach. At last Peter responded, but in a manner very different from that which they expected. In the years since the last patriarch had died, Peter had traveled abroad and seen much of other religions in both Catholic and Protestant countries. The Roman church, of course, was administered by a single man, but in Protestant lands the churches were administered by a synod or assembly or board of administrators, and this idea appealed to Peter. Having already reformed his civil administration by putting government in the lands of ministries or colleges, he was ready to impose a comparable structure on the church. In the latter part of 1718, Peter entrusted to Prokopovich the drafting of a church charter called the Ecclesiastical Regulation, which was to promulgate a new administrative structure for the Russian Orthodox Church. Prokopovich worked for many months, and the document is his most important achievement, but every section was read, revised and sometimes rewritten by Peter himself.