Year Europe Asia in sq. miles 1682 approx. 79,345 185 781 1725 82 687 192 882 1795 95 173 210 621 1825 104 926 234 945 1867 106 951,07 272 689,74 Total: 379,630.81 Caspian and Aral Seas 9,680.63 The total territory of the empire is 389,311.44 sq. miles5

At the time of the death of Alexander II (March 1, 1881), when the territorial growth was actually over, the territory of the state was, after the annexation of Turkestan, 403,060.43 square miles (i.e., 22,189,368.3 square kilometers, or 19,498,188.3 square versts). During the reign of the last two sovereigns, Alexander III and Nicholas II, taking into account some gains under Alexander III and small losses (half of the island of Sakhalin) under Nicholas II, the entire territory of the empire amounted (on January 1, 1910 and until July 20, 1914) 394,462 square miles (i.e., 21,735,995 square kilometers, or 19,099,165 square versts) [5].

The population movement due to the increase in territory was characterized by the fact that the indigenous Russian Orthodox population of the Muscovite state, being drawn into the processes of both private and state colonization, partly preceded state expansion (mainly to the East and further to Siberia), and partly followed it; But in both cases, the settlement did not take place in compact masses, but dispersed, in small groups among non-Russians and non-believers. Now representatives of other Christian denominations joined the number of subjects of the empire, as well as pagans, Muslims and Jews in increasing numbers. During the 18th and 19th centuries, Russia turned into a multi-confessional empire, where in the end the Orthodox population no longer constituted an absolute majority. The Church was faced with the question of its attitude to other Christian confessions, as well as missionary work. The task of missionary work turned out to be especially urgent in the new dioceses of Siberia, which, along with Orthodox Russian communities, also included territories with a population of other faiths. In the eighteenth and nineteenth centuries, the size of many dioceses was inversely proportional to the number of their Orthodox flock.

The growth of the state territory took place, if we take the position of the Muscovite state of the XVII century as the initial one, in three directions: to the west, to the south and to the east. Progress in each of these areas posed new tasks for the Church. Only the advance to the north was completed in the XV century near the shores of the White Sea.

The advance to the west began under Peter I and ended under Alexander I (1801–1825). The western regions annexed to Russia had, along with a large Jewish population, a population consisting exclusively of Catholics and Uniates, subject to the Pope and under the jurisdiction of the Roman Catholic Church, as well as Protestants, mostly Lutherans and, to a much lesser extent, followers of the Reformed doctrine [6]. Here the Russian Orthodox Church found herself in direct contact with the Western Christian confessions, and this confronted her with a whole range of problems connected with this kind of coexistence.

First, the question of missionary activity was brought to the fore, mainly among the Uniates. These were those whose ancestors had belonged to the Greek Orthodox Church before the union of 1596, and those who had been drawn into the union by the efforts of the Roman Catholic Church with the support of the Polish state authorities in the seventeenth and eighteenth centuries. Secondly, the Russian Church had to reckon with the possibility that the Orthodox population of the empire, and above all the Russian merchants, officials, etc., who lived in the western regions, could in one way or another be influenced by Western confessions. Naturally, this new question in the eyes of the leadership of the Russian Church was connected primarily with the problem of sectarianism. The position of the Church in the western regions was especially complicated by the state policy of Russification, which tended to use the services of the Church for this purpose. Forced to reckon with political and national state attitudes in her missionary work, the Church, as well as in relation to the Old Believers who broke away from her, found herself in a delicate position in relation to other Christian confessions, which often led to misunderstandings and misinterpretations of her actions and goals.

The expansion of the empire to the south to the shores of the Black Sea and the Sea of Azov meant the acquisition of new sparsely populated steppe regions in Tavria, the Crimea and the North Caucasus. In the XVIII-XIX centuries, these lands were gradually settled by Russians. From the second half of the 18th century, the government of Catherine II began to invite German colonists to the country, who belonged for the most part to various evangelical sects, settling them in these areas. Over time, German settlements spread throughout the vast expanse of the steppes [7]. From the second half of the nineteenth century, the religious influence of the German sectarians on the Orthodox population began to manifest itself with particular force, and the Russian Church came face to face with the rapidly developing sectarianism of the Protestant persuasion.

From the eighteenth century onwards, Russia's southward expansion was closely linked to the so-called "Eastern Question"; in addition, ties with the Orthodox Churches of the Balkan Peninsula and with the Patriarchates of the Middle East were strengthened. In the policy of the tsarist government towards Turkey and the Orthodox Slavic peoples of the Balkans, purely political interests were intertwined with national and religious ideas. The manifold ties of the Russian Church with the kindred Churches of the East depended to a large extent on the foreign policy of the state.

The advance to the east, which had begun even before the XVIII century, intensified in the XVIII and XIX centuries. New territorial acquisitions in Asia, with their ethnically, linguistically, and religiously mixed populations, led the Church to the need for missionary activity among pagans and Muslims. Only a few settlements of Orthodox people, far separated from each other, could serve as strongholds for such work in this vast area [8].

The increase in the total population of the empire, now mixed in terms of religion, until the second half of the nineteenth century was determined by means of so-called revisions, and only in 1897 was a regular general census of population introduced. With some reservations, we can rely on the following data:

1722–1724 (1st revision) 14 million 1762 (3rd revision) 19 million 1812 (4th revision) 41 million 1858 (10th revision) 74 million 1862 (incomplete accounting) 82 172 022 [9] 1897 (1st Population Census) 128 239 000 [10] (fixed) 128 924 289 [11] 1910 (computed) 163 778 800 1914 (computed) 178 400 000 [12]

Thus, the total population of the state from 1722 to 1724 increased almost 12 times.

As early as 1870, the confessional diversity of the population and its distribution over the territory of the state were regarded from the national-political point of view as unfavorable factors: "Although the Orthodox make up the vast majority of the population of the empire, nevertheless, the religious composition of the population cannot be recognized as completely favorable from a political point of view. Thus, on the western outskirts, the Catholic population is concentrated, which is hostile not only to Orthodoxy, but to everything Russian in general. In the Baltic provinces and in Finland, Protestants dominate. The eastern provinces, starting from the Kama and the Volga, are inhabited almost entirely by Muslims; in the Caucasus, however, the religious fanaticism of the Muslims was the cause of a bloody and prolonged war. Moreover, one should not lose sight of the harmful influence exerted on Orthodoxy by the schism; although the schismatics, due to their fragmentation into many sects, often hostile to each other, do not represent anything whole, nevertheless they all look at Orthodoxy with hostility" [13].

The percentage distribution of the population by religion gives the following picture: