It is alleged that the great aim of his life was to reform the Church on [[Calvinism|Calvinistic]] lines, and to this end he sent many young Greek theologians to the universities of Switzerland, the northern Netherlands and England. In 1629, his famous ''Confessio'' (Calvinistic in doctrine) was published in Latin, but as far as possible accommodated to the language and creeds of the Orthodox Church. From 1629 to 1633, it appeared in two Latin editions, four French, one German and one English. The "Confession" started a controversy in the Eastern Church which culminated in 1672 in the convocation by [[Dositheus II Notarius of Jerusalem|Dositheus]], [[Patriarch of Jerusalem]], of a [[synod]] by which the Calvinistic doctrines were condemned. Since then, eminent historians, theologians, and researchers have attempted to clarify whether Cyril Lucaris was the actual author of the "Confession" attributed by the Calvinists to him. While Cyril denied it verbally a number of times and proclaimed his Orthodox faith in his letters as well by his attitude, he did not disavow the "Confession" in writing. The orthodoxy of Cyril Lucaris himself has continued to be a matter of debate in the Eastern Church. Even Dositheus, in view of the reputation of the great patriarch, thought it expedient to gloss over his [[heterodoxy]] in the interests of the Church.
Cyril was also particularly well disposed towards the Anglican Church, and his correspondence with the [[Archbishop of Canterbury|Archbishops of Canterbury]] is extremely interesting. Through his contacts with the Church of England, he also set up a program of sending young Greeks to England to study. Among these students was the youth from Macedonia, [[Metrophanes (Kritopoulos) of Alexandria|Metrophanes Kritopoulos]] who later would become Patriarch of Alexandria. Both Cyril and Metrophanes were lovers of books and manuscripts, and acquired manuscripts that today adorn the Patriarchal Library. Cyril also presented King James I of England with a fine manuscript of the Holy Bible, known as Codex Alexandrinus. He also sent a manuscript of the [[Pentateuch]], with Arabic translation, to Laud, Archbishop of Canterbury.
While Cyril was several times [[deposition|deposed]] temporarily and banished at the instigation of his orthodox opponents and of the [[Jesuit]]s, who were his bitterest enemies, his death came suddenly. When the Ottoman Sultan Murad IV was about to set out for the Persian War, the [[patriarch]] was accused of a design to stir up the Cossacks. Thus, to avoid trouble during his absence, the sultan had Cyril strangled by the [[Janissaries]] in [[June 27]], 1638. His body was thrown into the Bosporus and was later recovered after being washed ashore on Halki Island. His body was buried at the Monastery of Panagia Kamariotissa on Halki by Patr. Parthenius I.