The period covers the beginning of Christianity until before the promulgation of the Nicene Creed at the First Council of Nicaea.

Nicaea served as the interim capital city of the Byzantine Empire between 1204 and 1261, following the Fourth Crusade in 1204, until the recapture of Constantinople by the Byzantines in 1261.

* Nicaea ( present-day İznik, another important city in Bithynia, and the interim Byzantine capital city between 1204 and 1261 ( Empire of Nicaea ) following the Fourth Crusade in 1204, until the recapture of Constantinople by the Byzantines in 1261.

The peace was maintained until 1222, at which point the resurgent power of Nicaea felt sufficiently strong enough to challenge the Latin Empire, by that time weakened by constant warfare in its European provinces.

It was re-occupied by the Despote of Epirus Michael II until 1259 when the Despotate was defeated by the Byzantine Empire of Nicaea in the Battle of Pelagonia.

This group believes very explicitly that the " Great Apostasy " began in AD 325 with the Council of Nicaea and continued until June 13, 1903, when Bishop Ambrose Jessup Tomlinson restored the Church, and that in the interim there was no actual theocratic governmental formed ( as Jesus formed it ) Church of God upon the earth, but that born-again people were abundant and continued to be " saved " or " born again " according to the Bible.

Constantinople was not founded ( that is, renamed from " Byzantium ") until after the First Council of Nicaea ( 325 ).

In the end, a uniform method of computing the date of Easter was not formally addressed until the First Council of Nicaea in 325.

David Komnenos, the younger brother of Alexios, expanded rapidly to the west, occupying first Sinope, then Paphlagonia and Heraclea Pontica ( modern Samsun province and the coastal regions of Kastamonu, Bartın and Zonguldak ) until his territory bordered the Empire of Nicaea founded by Theodore I Laskaris.

On July 1, they defeated Kilij at the Battle of Dorylaeum, and by October they reached Antioch ; they would not reach Jerusalem until two years after leaving Nicaea.

* 1259 – September – The Empire of Nicaea defeats the Principality of Achaea at the Battle of Pelagonia, ensuring the eventual reconquest of Constantinople in 1261.

* September – Battle of Pelagonia: The Empire of Nicaea defeats the Principality of Achaea, ensuring the eventual reconquest of Constantinople in 1261.

John IV Doukas Laskaris ( or Ducas Lascaris ) ( Greek: Ιωάννης Δ ΄ Δούκας Λάσκαρις, Iōannēs IV Doukas Laskaris ) ( December 25, 1250 – c. 1305 ) was emperor of Nicaea from August 18, 1258 to December 25, 1261.

After Michael's conquest of Constantinople on July 25, 1261, John IV was left behind at Nicaea, and was later blinded on Michael's orders on his eleventh birthday, December 25, 1261.

He recovered Constantinople from the Latin Empire in 1261 and transformed the Empire of Nicaea into a restored Byzantine Empire.

Although a residual Byzantine state known as the Empire of Nicaea survived the Crusader onslaught and eventually recovered Constantinople ( 1261 ), many of the original Byzantine territories, including Paros, were lost permanently to the crusading powers.

* Laskarid Dynasty ( 1204 – 1261 ), in exile in Nicaea

The Crusaders then installed a Latin Patriarch in Constantinople, while Theodore simply created a new Greek Patriarchate in Nicaea, which was eventually restored in Constantinople with the rest of the Empire in 1261.

# REDIRECT List of Byzantine emperors # Laskarid dynasty ( Empire of Nicaea, 1204 – 1261 )

1305 ), Emperor of Nicaea from 1259 to 1261

It was through this gate that the forces of the Empire of Nicaea, under General Alexios Strategopoulos, entered and retook the city from the Latins on 25 July 1261.

The Empire of Nicaea had, in 1261, succeeded in retaking Constantinople, extinguishing the feeble Latin Empire.

After the Fourth Crusade, members of the family fled to the neighboring Empire of Nicaea, where Michael VIII Palaiologos became co-emperor in 1259, recaptured Constantinople and was crowned sole emperor of the Byzantine Empire in 1261.

It too, however, was subject to gradual debasement: under the Empire of Nicaea ( 1204 – 1261 ), its gold content fell gradually to 18 carats, under Michael VIII Palaiologos ( r. 1259 – 1282 ) to 15 and under his son and successor Andronikos II Palaiologos ( r. 1282 – 1328 ) to 12 carats.

In his youth, his father was forced to mortgage him to Venetian merchants to raise money for the support of his empire, which was lost to the Empire of Nicaea in 1261.

By 1261 Mitso Asen was decisively defeated, and sought asylum with Michael VIII Palaiologos, the emperor of Nicaea.

With the virtual disappearance of the Byzantine fleet after the Fourth Crusade, the title was retained as an honorific in the Empire of Nicaea, where Michael VIII Palaiologos ( r. 1259 – 1282 ) assumed the title when he became regent for John IV Laskaris ( r. 1258 – 1261 ).

Nicaea (; ) was a Hellenic city in northwestern Anatolia, and is primarily known as the site of the First and Second Councils of Nicaea ( the first and seventh Ecumenical councils in the early history of the Church ), the Nicene Creed ( which comes from the First Council ), and as the capital city of the Empire of Nicaea.

) When Constantinople became the capital of the Eastern Empire, Nicaea did not lose in importance ; for its present walls, which were erected during the last period of the Empire, enclose a much greater space than that ascribed to the place in the time of Strabo.

Byzantine resistance in unconquered sections of the empire such as Nicaea, Trebizond, and Epirus ultimately liberated the capital and overthrew the crusader states.

Kilij Arslan then marched at the head of the Turkish Oghuz Yiva tribe army and set up his capital at Nicaea, replacing Amin ' l Ghazni, the governor appointed by Malik Shah I.

Nicomedia was the metropolis of Bithynia under the Roman Empire ( see Nicaea ), and Diocletian made it the eastern capital city of the Roman Empire in 286 when he introduced the Tetrarchy system.

The son of Osman, Orhan I, conquered Nicaea in 1331 and Nicomedia in 1337 and established the capital in Bursa.

Nicaea ( İznik ), located on the eastern shore of Lake İznik, had been captured from the Byzantine Empire by the Seljuk Turks in 1081, and formed the capital of the Sultanate of Rüm.

Constantine I undertook major reforms of Imperial administration and military organisation, founded a new Imperial capital at Constantinople on November 8, 324, summoned the first Christian ecumenical council ( I Nicaea, 325 ), and became the first Christian Emperor in 337.

In the East, the disastrous Battle of Manzikert in 1071 had resulted in the loss of Asia Minor, the Empire's military and economic heartland, to the Seljuk Turks, who by 1081 had established their capital at Nicaea, barely a hundred miles south of Constantinople.

* 1258 – Regent George Mouzalon and his brothers are killed during a coup headed by the aristocratic faction under, paving the way for its leader, Michael VIII Palaiologos, to ultimately usurp the throne of the Empire of Nicaea.

At that point the deposed emperor was ransomed by Michael I of Epirus, who sent him to Asia Minor, where Alexios ' son-in-law Theodore I Laskaris of the Empire of Nicaea was holding his own against the Latins.

The Latin Empire, Empire of Nicaea, Empire of Trebizond, and the Despotate of Epirus.

In the history of Christianity, the First seven Ecumenical Councils, from the First Council of Nicaea ( 325 ) to the Second Council of Nicaea ( 787 ), represent an attempt to reach an orthodox consensus and to unify Christendom under the State church of the Roman Empire.

With Constantinople occupied, claimants to the imperial succession styled themselves as emperor in the chief centers of resistance: The Lackarid dynasty in the Empire of Nicaea, the Komnenid dynasty in the Empire of Trebizond and the Doukid dynasty in the Despotate of Epirus.

In 325 A. D., following the First Council of Nicaea, departures from the beliefs of the state Church were classified as civil violations within the Roman Empire.

The city of Nicaea ( second only to Constantinople in the Byzantine Empire ) surrendered to him after a three-year siege in 1331.

It met in AD 787 in Nicaea ( site of the First Council of Nicaea ; present-day İznik in Turkey ) to restore the use and veneration of icons ( or, holy images ), which had been suppressed by imperial edict inside the Byzantine Empire during the reign of Leo III ( 717 – 741 ).

* Theodore I Lascaris flees to Nicaea after the capture of Constantinople, and establishes the Empire of Nicaea ; Byzantine successor states are also established in Epirus and Trebizond.

* The Second Council of Nicaea ends the first iconoclastic period in the Byzantine Empire.

* John III Ducas Vatatzes becomes Byzantine Emperor ( in the Empire of Nicaea ).

* Theodore I Lascaris, founder of the Byzantine Empire of Nicaea

The Empire of Nicaea succeeded in capturing Constantinople and the rest of the Latin Empire, thus re-establishing the Byzantine Empire.

* Theodore II Lascaris, Byzantine Emperor ( in exile in the Empire of Nicaea ), successfully concludes a military campaign started a year earlier to recover Thrace from the Bulgarians.

* Theodore II Lascaris, Byzantine Emperor ( in exile in the Empire of Nicaea ), conducts a military campaign to recover Thrace from the Bulgarians.