Sylvester Syropoulos was a patriarchal official and member of the Byzantine delegation to the Council of Florence in 1438– 1439 which enacted Union between the Catholic and Orthodox churches. Syropoulos wrote Memoires of his experiences at the council between 1443 and 1445. Laurent argues that a later version was written around 1461.

Syropoulos was born in Constantinople around 1400 into a well- off family and received an excellent education. He had a career as a patriarchal official and had the titles of Megas ekklesiareches and dikaiophylax. He died sometime after 1453. At the Council of Florence he signed the Decree of Union between the churches under intense pressure. Once he returned home, he repudiated the Union and supported the anti- Unionist cause.

The Memoirs serve a clear purpose in exonerating Syropoulos for his support of the Union after he had repudiated that position. The narrative explains why the delegates were made to accept the Union, even though it contradicted their principles, and implicitly makes a case for the rejection of the Council's Decree of Union. The Memoirs do not engage in theological or philosophical debates on the issues at hand in ecclesiastical Union. Rather they focus on personalities and politics. Syropoulos's eschewal of theology may be a strategy for distancing himself from the decisions of the council. Gill argues that the Memoirs are not historically reliable in comparison with the Acts of the Council, a position rejected by Geanakoplos. The level of detail in the narrative suggests that Syropoulos may have used a diary or other records of his experiences in writing his memoirs.

The text does not conform to the stylistic conventions of Greek historical writing. The opening of the text is lost, so it is impossible to know if it had an introduction that placed it in the tradition of classicizing historiography. The memoirs are written in a colloquial and vernacular style. It is organized into twelve sections (the first is lost), each entitled an apomnemoneumaton, a memoir. This term was used to title the sections of Xenophon's dialogues in defense of Socrates and of Diogenes Laertius's Lives of Philosophers. Syropoulos's choice to use this term for his writing may have been intended to align it more with biographical and apologetic texts than with historical writing.