The ecumene (US) or oecumene (UK; Greek: οἰκουμένη, oikouménē, lit. "inhabited") was an ancient Greek term for the known world, the inhabited world, or the habitable world. Under the Roman Empire, it came to refer to the civilized world and the secular and religious imperial administration. In present usage, it is used as the noun form of "ecumenical" and describes the Christian Church as a unified whole or the unified modern world civilization. It is also used in cartography to describe a type of world map (mappa mundi) used in late Antiquity and the Middle Ages.
Eratosthenes of Cyrene (276–196 BC) deduced the circumference of the Earth with remarkable accuracy. The Greek cartographer Crates created a globe about 150 BC. Claudius Ptolemy (AD 83–161) calculated the Earth's surface in his Geography and described the inhabited portion as spanning 180 degrees of longitude (from the Fortunate Isles in the west to Serae and Serica (China) in the east) and about 80 degrees of latitude (from Thule in the north to anti-Meroe below the equator). Ptolemy was well aware that Europe knew only about a quarter of the globe and his erroneous belief that the Indian Ocean was landlocked led to expectation of an unknown land (terra incognita). In fact, symmetry led him to expect that there should be three other continents to balance the ecumene: Perioeci (lit. "beside the ecumene"), Antoeci ("opposite the ecumene"), and the Antipodes (“opposite the feet”).
By that time, the Greek term had come to refer more specifically to the civilized world and then simply the Roman Empire. This usage continued after the Diocletian Reforms and the Byzantine emperors used it to refer to their imperial administration. Constantinople was the "Ecumenical City" and, after 586, its patriarch was known as the "Ecumenical Patriarch". Pope Gregory I objected to the adoption of this style by John the Faster, as it implied a universal jurisdiction he believed to be held by Rome. His Fifth Epistle berates John for having "attempted to seize upon a new name, whereby the hearts of all your brethren might have come to take offence", despite the title having been granted at the emperor Maurice's behest. The name continues to be borne by the Greek Orthodox patriarchs, although with the more restricted sense that they are the bishops of the former imperial capital.
In the 20th century, the term has been employed to refer to unified Christian Church which is the ultimate goal of Ecumenism, a movement to promote cooperation among the various denominations of the religion. The movement is not accepted by many Christian groups. The work of ecumenism takes place in the form of negotiations conducted between committees of various denominations and also through the deliberations of inter-denominational organizations such as the World Council of Churches. Relevant issues include Baptism, the Eucharist and Ministry.
In the context of cultural history, the term was first used in an academic sense by Lewis Mumford in his work, Technics and Civilization (1934) and later popularized by William McNeill's "Rise of the West". McNeill suggested that a single global ecumene was created through the dominance of European political institutions, science, technology, and economic forms from the late 18th century onwards. One could argue that prior to the great voyages of discovery, initiated by Christopher Columbus, Vasco da Gama, and Ferdinand Magellan, there were originally two separate ecumenes—one covering the Old World and one the New. It was the Spanish conquistadores that fused this second ecumene to the first to create a single integrated "world system".
- The author J.R.R. Tolkien described his Middle-earth setting for his fiction as equivalent to the Greek ecumene, the abode of Man.
- In the Demon Princes series of science fiction novels by Jack Vance, the Oikumene is the term used for the human-inhabited worlds of the galaxy.
- In the science fiction novel Time's Eye co-authored by Arthur C. Clarke and Stephen Baxter Oikoumene is a grassroots religious unification movement bridging the divide between Catholicism and Islam.
- In The Left Hand of Darkness and other fiction by Ursula K. Le Guin, the Ekumen is a loose confederation of inhabited worlds, linked by instantaneous communication, but separated by slower-than-light travel.
- In the science fiction trilogy The Golden Age, by John C. Wright, a polity called the Golden Oecumene spans all of the Solar System.
- In the Halo universe, more particularly in Halo: Combat Evolved Anniversary and the Forerunner Saga novels, the Forerunner Ecumene spanned the galaxy more than 100,000 years ago. Forerunner society was divided into five main social classes, called "rates" (in ascending order of social standing/power): 'Engineers', 'Warrior-Servants', 'Lifeworkers', 'Miners', and 'Builders'.
- Oxford English Dictionary. "œcumene, n."
- Klein, Samuel John (2005), "Oecumene", Cartography Word of the Day, Designorati, retrieved 2008-01-03
- Although Ptolemy did not measure latitude with degrees but with hours of midsummer daylight, from 12 at the equator to 24 in the arctic.
- Schaff, Philip (1882), "Gregory and the Universal Episcopate", History of the Christian Church, IV: Mediaeval Christianity: A.D. 590–1073, Peabody, Massachusetts: Hendrickson Publishers; 3rd edition (July 1, 1996), ISBN 978-1-56563-196-0, retrieved 2008-01-03
- St Gregory the Great. Epistle V, §xviii.
- "The Universal Patriarch", The Witness (PDF), XXV, No. 13, August 3/16, 1981, Boston, Massachusetts: Holy Transfiguration Monastery, retrieved 2008-01-03
- Mumford, Lewis (1934), Technics and Civilization, New York: Harcourt, retrieved 2008-01-03
- Halopedia – Ecumene
- Halopedia – Rate