Despite all the donations and properties which the Monastery had received, the total extent of its productive landholdings outside the Athonite peninsula were reduced, while the number of metochia remained more or less the same. This situation was caused by the illegal settlement on or use of land by local Christian and Muslim villagers, and the need to pay the exorbitant taxes levied by local Ottoman officials, phenomena which were a reality the monks had to confront almost daily. The metochia frequently had to be mortgaged to Muslims, even for long periods of time, in order for the monks to be able to pay their required taxes.
Around the 18th century, an important change in the history of the Monastery occurred: The population of monks who up until that time had mainly been Slavic-speaking (i.e. Serbs or Bulgarians) were gradually replaced by Greeks. Thus, after 350 years of operating with a majority of Slavic-speaking monks, the population of St Pavlos Monastery once again had a majority of Greek-speaking monastics. The reason for this change is not known. It is possible that the Austro-Ottoman wars of 1684-1699 ended the Ottoman control over Mt Athos and the areas of greater Macedonia and Serbia from which the monks mainly had come to the Monastery. Moreover, the presence of the Greek-speaking Fanariotes in the countries around the Danube helped increase the number of Greek monks. Finally, the general spiritual and economic development of Hellenism during the 18th century, together with the larger number of Greek monks residing at the monasteries, resulted in the predominance of the Greek language on the Athonite peninsula.
The change did not immediately help the Monastery. During the 18th century, the difficult economic situation continued, and the retention of the properties outside the Athonite peninsula was an enormous challenge. At the end of the century, however, a figure appeared who would change the picture of the Monastery and would lay the foundation for its future development. This figure was the Archimandrite Anthimos Komninos.
According to tradition at the Monastery, Anthimos, a member of a wealthy family, was born in Silyvria in eastern Thrace in 1762. By 1788, he is mentioned in sources as being a deacon at the Monastery, while in 1791, he became the overseer of the wealthy metochi Zitianos in Vlachia. This provided him with the opportunity to generate a great profit, which he invested in the Monastery he had chosen for his life of repentance. In 1798 and 1806, he financed the production of two copper engravings depicting the Monastery, which were a necessary accessory for the monks who travelled to distant areas for the purpose of soliciting donations.
In 1814, he left Vlachia and took up residence in the Monastery, having had already drawn up an ambitious plan in 1804 for a structural renovation programme. His goal was the expansion of the monastic complex towards the south, which required the removal of rocks from a large area in order to widen the interior of the Monastery and to create a larger courtyard. The construction of a new cathedral was also included in his plans. By 1821, it is known that Anthimos had succeeded in constructing a new bell tower and a number of fountains, to lay the foundations of the new cathedral, and to finance work in the hospital and in the refectory.
The outbreak of the Greek Revolution abruptly interrupted his renovation projects, since he himself, likely a member of the Company of Friends (a secret group involved with organizing and financing the Greek Revolution), left Mt Athos first for Italy and from there to Vlachia. He died in Bucharest in 1828. In his will, which is kept in the archives of the Monastery, Anthimos left about 430,000 grosia to the Monastery, a huge sum for that time, a proof of his managerial abilities and of his great contributions to the Monastery.