City in northern Syria and an important center of Christianity in the Middle East today as the seat of a total of nine bishoprics (Syr. Orth., Syr. Catholic, Chald., Maron., Melk. Orth., Melk. Catholic, Armenian Orth., Armenian Catholic, Latin). Aleppo, nicknamed ‘Grey Aleppo’ (Ḥalab al-šahbāʾ) in Arabic, owes its military and commercial importance to its imposing citadel and its favorable position on the trade route linking the nearby Mediterranean coast with Mesopotamia and areas beyond. Aleppo’s history goes back at least to the second millenium BC. The earliest known names of Aleppo are cognates of the modern name ‘Ḥalab’, but Seleucus Nicator (d.  281  BC) who founded a Greek colony here named it after ‘Beroea’ in Macedonia, and it is by that name that Aleppo is normally known in older Syriac literature. Aleppo came under Roman rule in 64 BC. After the Arab conquest in 636, Aleppo first rose to prominence under the Ḥamdānid Sayf al-Dawla (945–67). Aleppo later became the seat of lines of Zangids (1129–83) and Ayyūbids (1183–1260). Aleppo was taken by the Mongols in 1260 and a little later by the Mamlukes. Under the Ottomans (1516–1918), Aleppo became the capital of a province covering much of today’s northern Syria and a significant part of Turkey (including Antioch, Alexandretta/Iskenderun, and ʿAintab/Gaziantep). For much of that period, it was the third largest city in the Ottoman Empire after Istanbul and Cairo, and the Christians, including Syr. Christians, as well as a larger number of Melkites and later an increasing number of Armenians, then played an important role in the life of the city, one noteworthy member of the Aleppine Syr. Catholic community from the period being the world-famous chess player Philip Stamma (ca. 1705–55). Aleppo is today the largest city in Syria with a population of ca. 1.7 million (2.85 million in the larger conurbation, in 2008).

The first known bp. of Aleppo is Eustathius, who became patr. of Antioch and attended the Council of Nicaea in that capacity. Bp. Peter of Aleppo was a supporter of Philoxenos of Mabbug at the Synod of Sidon in 511, while Bp. Antoninus was among the Miaphysite bishops exiled with Severus of Antioch under Emperor Justin.

The first known Syr. Orth. bp. after the reorganization of the church in the mid-6th cent. is Matthew (644–669). Among his successors was Bar ʿEbroyo (ca. 1253–64), who was the bp. there when the city fell to the Mongols in 1260. Little is known about the Syr. Orth. community in the subsequent period until the beginning of the 16th cent., when we first hear of a Syr. Orth. (later Syr. Catholic) church of the Mother of God in the Christian quarter of Judayda (Jdeideh), and we find Aleppo included, along with Damascus and Ḥama, in the title of Metr. Grigorios Yawseph the Iberian of Jerusalem (metr. 1515–37). From the second half of the 16th cent. onwards, we frequently hear of visits to Aleppo by Syr. Orth. patriarchs, including Ignatius Pilatus I ( patr. 1591–97) who died and was buried in Aleppo. The Syr. Orth. community in Aleppo, reduced to a small number through large-scale conversions to the Syr. Catholic Church since the latter half of the 18th cent., was reinforced in the 20th cent. by refugees fleeing the atrocities in areas now in the Republic of Turkey. These refugees included a group from Edessa, who migrated to Aleppo en masse in 1924, as well as those from the area around Mardin.

As a center of Latin missionary activity since the beginning of the Ottoman era, with Capuchins, Jesuits and Carmelites present in the city by 1526, Aleppo played an important role in the formation of the Syriac Catholic Church. Andrew Akhījān ( patr. 1662–78) worked and was elected patr. in Aleppo, while Michael Jarweh ( patr. 1782–1800) was born in Aleppo and was Metr. of Aleppo prior to his elevation to the patriarchate. The central role Aleppo continued to play in the life of the Syr. Cath. Church is reflected in the fact that five out of the thirteen successors of Michael Jarweh have been natives of Aleppo (Michael Ḍāhir, Peter Jarweh, George Chelhot, Antony Ḥayek, Peter ʿAbd al-Aḥad), while two others were Metr. of Aleppo before ascending to the patriarchate (Ignatius Ephrem Raḥmani, Gabriel Tappuni).

The E.-Syr. see of Aleppo is attested in the 11th cent. and is also mentioned as a suffragan of Damascus in a list of bishoprics appended, in a 13th-cent. ms., to the canonical works of Elias of Damascus (ca. 900), but it was probably extinct by the 13th cent. Nothing is then heard of the E.-Syr. presence in Aleppo until the 17th cent. The Chald. diocese of Aleppo, founded as a patriarchal vicariate in 1901 and raised to the status of an eparchy in 1957, today covers the whole of Syria.

The presence of an early Maronite community in Aleppo in 727 is recorded in the Chronicle of Michael Rabo. Significant presence of Maronites in the modern period dates from the 17th cent., with Maronite bishops regularly resident in the city since 1686. Aleppo played an important role in the life of the Maronite Church as one of her few urban centers, and the Maronite school there produced such men as the three founders of the Maronite Aleppine Order (later Mariamites) and the scholar-bishop Germanus Farḥāt (bp. of Aleppo 1725–32). The Maronite woman mystic Hindiyya al-ʿUjaymī was born in Aleppo in 1720.

In the first decade of the 20th cent., there were reported to be approximately 35,000–40,000 Christians in the city, making up about one third of the total population and including: 3,500 Syr. Catholics (4,000 in the diocese), 50 Syr. Orth. (500 in the diocese), 250 Chald. and 3,600 Maron. (Karalevsky); as well as 1,200 Melk. Orth., 10,000 Melk. Catholics, 15,000 Armenian Orth., 5,500–7,000 Armenian Catholics, 1,100 Latins and 1,500 Protestants (Tournebize). The numbers reported today for the Syriac dioceses of Aleppo are: Syr. Orth. 15,000 (in 2003, Zinda Magazine); Syr. Catholic 8,000 (in 2006, Annuario pontificio); Chald. 15,000 (in 2006, Annuario pontificio, for whole of Syria); Maron. 4,000 (in 2006, Annuario pontificio). The actual numbers (esp. for the Chaldeans) will have been increased significantly by those fleeing insecurity in Iraq since 2003.

Little is known about the sites of the medieval Syriac churches in Aleppo. The churches dating from the Ottoman period are found in the traditional Christian quarter in Judayda just north of the medieval city. These include the Melkite and Armenian churches concentrated in the Ṣalībat al-Judayda Quarter, as well as the Syr. Catholic Church of Mār Āsyā al-Ḥakīm (formerly Mother of God) a little to the east, and the Maronite Cathedral of Mar Eliya to the north. A  number of newer churches, including the Syr. Catholic Cathedral (Umm al-Intiqāl/Assumption, 1970), are found in the ʿAzīziyya District to the north of Judayda. The Chaldean Cathedral and the Syr. Orth. Cathedral of Mar Ephrem lie further north in Sulaymāniyya. Further churches belonging to the Syriac communities are found in the ‘Old Syriac Quarter’ (Ḥayy al-Suryān al-Qadīm) just behind the railway station to the northwest of the city center, a quarter established by migrants from Edessa (Mār Jirjis, Syr. Orth.; Mār Afrām, Syr. Catholic), and in the ‘New Syriac Quarter’ (Ḥayy al-Suryān al-Jadīd) further northwest (Sayyidat al-Suryān ‘Our Lady of the Syriacs’, Syr. Orth.).

Important collections of Christian Arabic and Syriac mss. are found in Aleppo at the Maron. Archiepiscopal Residence (over 1640 mss.), Fondation Georges et Mathilde Salem (most of Sbath Collection, no. 777–1321, and some additional mss.), Syr. Catholic Archiepiscopal Residence (ca. 500 mss.) and Syr. Orth. Archiepiscopal Residence and Church of Mar Jirjis (including the collection transferred from Edessa, ca. 225 mss.), as well as at the Melk. Catholic Archiepiscopal Residence (ca. 1,100 mss.).

A large number of ruined Byzantine churches are found in the so-called ‘Dead Cities’ in the hills to the west of Aleppo, including the ruins of the huge basilica built around Shemʿun the Stylite’s pillar at Qalʿāt Simʿān (approx. 30 km. west-northwest of Aleppo).