The Holy See of Cilicia (also known as "the Catholicossate of the Great House of Cilicia") is one of two sees of the Armenian Apostolic Church. Since 1930, it has been headquartered in Antelias, Lebanon. Aram I has been Catholicos of Cilicia of the Armenian Apostolic Church since 1995.

The origin of the Armenian Church dates back to the Apostolic age and according to the ancient tradition was established by St. Thaddeus and St. Bartholomew. In 301 AD, Christianity was officially accepted by the Armenians as the state religion.[citation needed]

St. Gregory the Illuminator, the patron Saint of the Armenian Apostolic Church, and King Tiridates III of Armenia, the ruler of the time, played a pivotal role in the official Christianization of Armenia.

St. Gregory the Illuminator became the organizer of the Armenian Church hierarchy. From that time, the heads of the Armenian Church have been called Catholicos and still hold the same title.

St. Gregory chose as the site of the Catholicossate then the capital city of Vagharshapat, in Armenia. He built the pontifical residence next to the church called "Holy Mother of God" (which in recent times would take on the name of St. Etchmiadzin).

In 485 AD, the Catholicosate was transferred to the new capital Dvin. In the 10th century it moved from Dvin to Dzoravank and then to Aghtamar (927 AD), to Arghina (947 AD) and to Ani (992 AD).

After the fall of Ani and the Armenian Kingdom of Bagradits in 1045, masses of Armenians migrated to Cilicia. The Catholicossate, together with the people, settled there.

The seat of the church (now known as The Catholicossate of the Great House of Cilicia) was first established in Sivas (1058 AD) moving to Tavbloor (1062 AD), then to Dzamendav (1066 AD), Dzovk (1116 AD), Hromgla (1149 AD), and finally in Sis (1293), the capital of the Cilician Kingdom.

After the fall of the Armenian Kingdom of Cilicia, in 1375, the Church also assumed the role of national leadership, and the Catholicos was recognized as Ethnarch (Head of Nation). This national responsibility considerably broadened the scope of the Church's mission.

In 1441, a new Catholicos was elected in St. Etchmiadzin in the person of Kirakos I Virapetsi of Armenia. At the same time residing Catholicos in Sis Gregory IX Mousabegian (1439–1446) remained as Catholicos of Cilicia.

Therefore, since 1441, there have been two Catholicossates in the Armenian Church with equal rights and privileges, and with their respective jurisdictions.

The primacy of honor of the Catholicossate of Etchmiadzin has always been recognized by the Catholicosate of Cilicia.

The city of Sis (modern-day Kozan, Adana, Turkey) was the center of the Catholicossate of the Great House of Cilicia for more than 6 centuries starting 1293, when the Catholicossate moved from Hromgla to Sis. In the First World War, most notably in 1915, the Armenian population and the monastery of St. Sophia of Sis, home of the Catholicossate (which dominated the town in early 20th century photographs) was destroyed.

The last residing Catholicos in Sis was Sahak II of Cilicia (Catholicos from 1902 to 1939). Sahak II followed his Armenian flock in exile from Turkey.

Sahak II after leaving the premises of the Catholicossate in Sis stayed at various locations in Northern Syria and in Lebanon, running the affairs of the Catholicossate.

Tha ailing Catholicos who served until 1939 was aided in his later years by Papken I of Cilicia who served as Coadjutor for the Catholicos from 1931-1936. Both clergy decided to acquire a plot of land in Antelias, Lebanon, to build there the new center of the Catholicossate.

By donations from Simon and Mathilde Kayekjian, the property of the Catholicosate was purchased from the American Committee for Relief in the Near East.

The latter charity which 1922-1928 had been running an Armenian orphanage on that same plot of land from 1922 to 1928. It was only natural that the Catholicosate would consider that spacious plot to build the new Catholicossate on.

The main cathedral called St. Gregory the Illuminator Cathedral was built through the donation of an unknown benefactor, whose name was kept a secret until his death according to his wishes. His name, Sarkis Kenadjian, was revealed only after his death.
 
Memorial chapel to the Armenian Genocide at the Catholicossate premises in Antelias
 
The Veharan, the residence of the Catholicos in Antelias, Lebanon
 
Holy Mother of God Church (Sourp Asdvadzadzin) at the seminary in Bikfaya

A chapel in memory of the one and a half million Armenian martyrs was built, followed by a residence for the Catholicos (called Veharan) and a new Seminary building, constructed one after the other. Catholicos Sahak II died in 1939. However the Museum is a much later development and built and inaugurated in 1997.

The complex of the Catholicossate of the Great House of Cilicia (in Antelias, Lebanon) includes:
St. Gregory the Illuminator Cathedral built in 1940
The Catholicossate Library (established 1932)
"Cilicia" church museum (1997)
Chapel dedicated to the memorial of the victims of the Armenian Genocide.
The "Veharan", the location of the catholicos' residence.

The Catholicossate also runs a printing house that publishes various religious, cultural and historical books and publications, as well as "Hask" the official periodical of the Catholicossate and the annual "Hask Armenological Review".

The Catholicossate complex also includes the mausoleum / cemetery where a number of the heads of the Catholicossate of the Great House of Cilicia are buried. For a certain period, the Catholicossate also hosted an elementary Armenian school that was closed later on.

A theological seminary is located in the nearby mountains in Bikfaya that also serves as summer residence for the Catholicos and the clergy.

The Holy See of Cilicia has a Central Committee having both Religious and Lay members.

The following were elected as members of the Religious Committee: Archbishop Ardavazt Terterian, Archbishop Gomidas Ohanian, Archbishop Varoujan Hegelian, Archbishop Khajag Hagopian, Archbishop Sebouh Sarkissian, Archbishop Moushegh Mardirossian, Bishop Kegham Khatcherian, Bishop Nareg Alemezian, Bishop Shahan Sarkissian, Bishop Shahe Panossian V. Rev. Fr. Krikor Chiftjian, V. Rev. Fr. Yeghishe Mandjigian and Father Masis Tchobouyan.

Elected as members of the Lay Committee were Hagop Ateshian, Vicken Kassabian, Dikran Djinbashian, Dr. Bedros Karadjerdjian, Dr. Hratch Hadjetian, Dr. Vahe Yacoubian, Dr. Dertad Mangigian, Khajag Dikirdjian, Dr. Jirayr Basmadjian, Hagop Yapoudjian, Dr. Levon Tavtian, Daron Avedissian and Ara Demirdjian, representing the worldwide dioceses of the Catholicosate of Cilicia.

(in parenthesis, the residence of the Prelate / Archbishop / Bishop)
United States (2 prelacies)
Prelacy of Eastern United States of America (in New York)
Prelacy of Western United States of America (in La Crescenta, California)
Canada:
Prelacy of Canada (in Montreal)
Lebanon
Diocese of Lebanon (in Beirut)
Diocese of Lebanon (in Anjar)
Diocese of Lebanon (in Bourj Hammoud)
Diocese of Lebanon (in Antelias)
Syria (three dioceses)
Diocese of Aleppo, Syria (in Aleppo)
Diocese of Jezireh, Syria (in Kamishli)
Diocese of Damascus, Syria (in Damascus)
Cyprus
Diocese of Cyprus (in Nicosia)
Greece
Diocese of Greece (in Athens)
Iran (3 diocese)
Diocese of Tehran, Iran
Diocese of Isfahan, Iran
Diocese of Tabriz, Azerbaijan, Iran
Gulf:
Diocese of Kuwait and the Persian Gulf Countries (in Kuwait)
Venezuela
Vicariate of Venezuela (in Caracas)

The Holy See of Cilicia is located in Antelias, Matn District at 33°55′5.79″N 35°35′7.18″E (33.918275, 35.585328), on a large plot overlooking the Beirut - Tripoli highway and the Mediterranean Sea.