Fifth Council of Constantinople is a name given to a series of six patriarchal councils held in the Byzantine capital Constantinople between 1341 and 1351, to deal with a dispute concerning the mystical doctrine of Hesychasm. These are referred to also as the Hesychast councils or the Palamite councils, since they discussed the theology of Gregory Palamas, whom Barlaam of Seminara opposed in the first of the series, and others in the succeeding five councils. 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.
As it became clear that the dispute between Barlaam and Palamas was irreconcilable and would require the judgment of an episcopal council. A series of six patriarchal councils was held in Constantinople on 10 June 1341, August 1341, 4 November 1344, 1 February 1347, 8 February 1347, and 28 May 1351 to consider the issues. Collectively, these councils are accepted as having ecumenical status by Orthodox Christians, some of whom call them the Fifth Council of Constantinople and the Ninth Ecumenical Council.
The dispute over Hesychasm came before a synod held at Constantinople in May 1341 and presided over by the emperor Andronicus III Palaeologus . The assembly, influenced by the veneration in which the writings of Pseudo-Dionysius were held in the Eastern Church, condemned Barlaam, who recanted.