The origin of the diocese goes back to the [[exarchate]] of the Moscow Patriarchate in Western Europe, just after the Russian revolution in 1917, chaired by [[Metropolitan]] [[Eulogius (Georgievsky) of Paris|Euloge (Guéorguievski)]]. Because of many problems with the Soviet controlled Mother Church, Metropolitan Euloge requested autocephalous status from Moscow, but was denied. Metropolitan Euloge did not believe that he and his flock were in the same situation as the refugees of the [[ROCOR|Karlovtsy Synod]], he was looking for what he could see as a canonical solution to the situation.
In 1931, Metropolitan Euloge temporarily left the [[Moscow Patriarchate]] and reluctantly joined the jurisdiction of the [[Patriarchate of Constantinople]]. The Orthodox who remained loyal to the Russian Orthodox Church in 1931 founded the parish of the ''Three Holy Hierarchs'' ([[Basil the Great]], [[Gregory the Theologian]]and [[John Chrysostom]]). Among its founders were Bishop [[Benjamin (
Fedtchenkov)]], the theologian [[Vladimir Lossky]], hiéromoine [[Athanasius (Netchaev)]]. An important role in the founding of new exarchate was played by the [[Fraternity of St. Photius]], it was chaired by Vladimir Lossky until 1931 .
In January 1931, the Moscow Patriarchate, then subjected to unprecedented persecution from the Soviet authorities, appointed [[Eleutherius (Bogoïavlenski)]] Metropolitan of Vilnius in place of Metropolitan Euloge. In March of that year, Bishop Benjamin became auxiliary bishop of the diocese and rector of the church of the Three Holy Hierarchs, which became in 1946 the headquarters of the new exarch of the Moscow patriarchate in France.
== Organization ==
The Diocese of Chersonese includes the parishes of the Moscow Patriarchate in Italy, Switzerland, France, Spain, and Portugal. Its current seat is the Three Holy
Hiearchs' Church in Paris, France, but planning for the construction of a large cathedral in central Paris in cooperation with the Russian and French governments is underway. In addition to the parishes, monasteries, and chapels under its care the Diocese of Korsun also operates a theological seminary in Épinay-sous-Sénart, France.