Pyrrhus was the Ecumenical Patriarch of Constantinople from 20 December 638 to 29 September 641, and again from 9 January to 1 June 654.

He was a supporter of Monotheletism, a christological doctrine propounded by the Emperor Heraclius

Heraclius

Heraclius was Byzantine Emperor from 610 to 641.He was responsible for introducing Greek as the empire's official language. His rise to power began in 608, when he and his father, Heraclius the Elder, the exarch of Africa, successfully led a revolt against the unpopular usurper Phocas.Heraclius'...

. In 638, with the support of Heraclius, he was elected to the patriarchal throne. In the unrest following the death of Heraclius, he was accused of plotting against the life of Constantine III and banished to Africa.

While in exile, in 645 he conducted with Maximus the Confessor

Maximus the Confessor

Maximus the Confessor was a Christian monk, theologian, and scholar. In his early life, he was a civil servant, and an aide to the Byzantine Emperor Heraclius...

 a public discussion on faith (Disputatio cum Pyrrho), after which he rejected Monothelitism, and visited Rome

Rome

Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...

 in 647. From there he continued to Ravenna

Ravenna

Ravenna is the capital city of the Province of Ravenna in the Emilia-Romagna region of Italy and the second largest comune in Italy by land area, although, at , it is little more than half the size of the largest comune, Rome...

 and returned to Constantinople

Constantinople

Constantinople was the capital of the Roman, Eastern Roman, Byzantine, Latin, and Ottoman Empires. Throughout most of the Middle Ages, Constantinople was Europe's largest and wealthiest city.-Names:...

, where he again reversed his position and re-embraced Monothelitism. He was excommunicated by Pope Theodore I

Pope Theodore I

Pope Theodore I , who was pope from November 24, 642, to May 14, 649, is considered a Greek, but was born in Jerusalem. He was made a cardinal deacon, and a full cardinal by Pope John IV....

 as a consequence, but succeeded in becoming again Patriarch in early 654, holding the office until his death on 1 June of the same year.