The Fifth Council of Constantinople was a series of councils held in Constantinople in 1341, 1347 and 1351, which exonerated St. Gregory Palamas' hesychastic theology and condemned the rationalistic philosophy of Barlaam of Calabria. The result of these councils is accepted as having the authority of an ecumenical council by Orthodox Christians who sometimes call it the Ninth Ecumenical Council. Principal supporters of the view that this series of councils comprises the Ninth Ecumenical Council include Metropolitan Hierotheos (Vlachos) of Nafpaktos, Fr. John S. Romanides, and Fr. George Metallinos.