Kleovoulos, whose church name was Eustathios, was born in 1824 at the village of Palladari of Prousa. After learning his first letters near his uncle (from the side of his mother), who was the abbot at the monastery of Eligmoi (next to the homonymous village also of Prousa), went to the school of Kios. From there he moved to Constantinople, where he entered the Great School of the Nation. In Constantinople Kleovoulos managed to rise to the higher ranks of the orthodox hierarchy thanks to the help and support of the ecumenical patriarch Gregorios VI (1835-1840), the later ecumenical patriarch and then metropolitan of Derkoi Germanos, as well as the great preacher of the church Panas.
He finished his studies at the Great School of the Nation thanks to the financial support of Germanos, who had by then become ecumenical patriarch Germanos IV (1842-1845) and immediately after went to the University of Athens, where he attended theology lessons. During this time he took great advantage from his close relationship with Konstantinos Oikonomos from the Oikonomos family, one of the leaders of the effort for the resolution of the problem which had started with the declaration of the independence of the Church of Greece from the Ecumenical Patriarchate.
Right after that he returned to Constantinople and in 1848, just 25 years old, was appointed as a professor at the Theological School of Chalke. For two years he taught Greek and Latin philosophy at the Theological School. In 1850 he was appointed as a tutor at the house of the Grand Logothetes Nikolaos Aristarches, after the recommendation of K. Oikonomou, who maintained very good relations with the former. In Aristarches’ house he taught until 1853. In this year he was ordained as a deacon and was sent by the patriarchate to Trebizond as the director (scholarches) of the schools there. In 1855 he returned to Constantinople, where he remained for three more years (until 1858) as the tutor at the house of Nikolaos Aristarches.
In 1858 he travelled to Europe once again to conclude his studies. He studied in the universities of Leipzig, Berlin and Paris. There he perfected his knowledge in Greek, Latin, French and German, as well as in philosophy, theology, philology, history, mathematics, chemistry and music. In Paris he collaborated with the French theological journal Unité Chrétienne, which was published by the French orthodox priest abbot Guetté and by the Russian Josef Vassilief.
When, in 1864, he returned to Constantinople, he took the position of the director of the Great School of the Nation. In the same year he became an archimandrite. He held the position of the director of the school for three years. In 1867 he became a Great Protosyngellos of the patriarch Gregorios VI, who had risen to the throne of the patriarch for a second time (1867-1871), basically aiming in settling the Bulgarian issue, which had by then reach a dangerous phase.
2. Activity of Eustathios as the metropolitan of Caesarea
In 1871, when the metropolitan of Caesarea Paisios II died, there was a great disagreement between the colony of the Cappadocians in Constantinople and the Ecumenical Patriarchate concerning the person who would succeed this very important prelate. The majority of the members of the Cappadocian colony in Constantinople preferred Kleovoulos as the successor of Paisios, whereas a part of the Cappadocians (mainly the ones still living at the villages of Anatolia), promoted the bishop of Nazianzos Gerasimos. On the other hand the patriarch Gregorios VI himself wanted to appoint as the metropolitan of Caesarea the metropolitan of Agchialos (and then of Smyrna) Basileios. Finally the first party manage to enforce its view (often using violent actions, like the public demonstrations outside the Ecumenical Patriarchate) and Kleovoulos was elected and ordained as a metropolitan of Caesarea on 30th September 1871.During his brief service at the metropolis of Caesarea, Eustathios tried to improve the educational level of the inhabitants of Cappadocia: right after his arrival the metropolitan led the foundation of a Cappadocian Educational Fraternity, whereas he also contributed to the foundation of school but also to the organization of the educational programs at the existing ones. He also tried to be constantly present with his preaching to the various villages of his metropolis, he did not manage, however, to finish his work: on 26th 1875 he died suddenly, bringing great sorrow to the province. His was replaced by the metropolitan of Mytilene Methodios.