The southern Slavs had in 1219 acknowledged the Empire of Nicaea as the heir to the Roman Empire and the center of Eastern Orthodoxy.

Rastko organizes the Serbian church, with its seat at Zica, near modern Kraljevo, into bishoprics headed by his former monastic colleagues and students.

He now embarks on a cultural and ecclesiastical renaissance that includes the establishment of schools and the beginnings of a medieval Serbian literature; he personally contributes a chronicle of his father's reign.

The writings of Stefan II and his brother are considered as the first works of Serbian literature.

Theodore's surviving brothers, Alexios and Isaac, protest the succession, and civil war breaks out.

The struggle for the Nicaean throne ends with the Battle of Poimanenon, fought in the winter of 1223/1224, in which John’s opponents, the two Lascaris brothers, are defeated and blinded in spite of the support they had acquired from the Latin Empire of Constantinople.

This victory opens the way for the recovery of most of the Latin possessions in Asia.

The crusaders of the Latin Empire of Constantinople had been decisively defeated by the Bulgarian Emperor Kaloyan in the battle of Adrianople (1205).

In 1225, Theodore Komnenos Doukas, self-proclaimed despot of Epirus, proclaims himself emperor in a direct challenge to the identical claim of Nicaean emperor John III.

Nicaean forces dispatched by John to fight Epirus lose at Adrianople in Thrace, and Theodore takes possession of the city.

John III, allied in 1224 to Bulgarian ruler Ivan II, had acquired territory in the Aegean and in Asia Minor but had failed to capture Constantinople.

Ivan had subsequently defected to the Latin side, but the Latin emperor Robert, threatened both by Nicaea in Asia and Epirus in Europe, sues for peace, which is concluded in 1225.

According to its terms, the Latins abandon all their Asian possessions except for the eastern shore of the Bosporus and the city of Nicomedia with the surrounding region.

Seljuq sultan 'Ala' ad-Din Kayqubad has meanwhile built on the accomplishments of his father and brother, having conquered most of the Mediterranean littoral up to the frontiers of Syria from 1221 to 1225.

The circumstances surrounding the failed negotiations to wed Robert, a weak and incapable ruler, to Eudocia are unclear, but George Akropolites states that the arrangement was blocked on religious grounds by the Orthodox Patriarch Manuel Sarentos: Robert's sister Marie de Courtenay was married to Emperor Theodore I Laskaris.

Accordingly, Robert, already Theodore's brother-in-law, could not also be his son-in-law.

Regardless, Robert had promised again to marry Eudocia but soon repudiated this engagement, and in 1227 (according to William of Tyre Continuator) secretly marries the Lady of Neuville, already the fiancée of a Burgundian gentleman.

Both the new wife of the Emperor and her mother are placed in a manor house owned by Robert.

The unnamed Burgundian gentleman somehow finds out and reportedly organizes a conspiracy against Robert and his new wife.

The knights of Constantinople partaking in the conspiracy proceed to capture the Empress and her mother.

The lips and nostrils of both women are cut off and then thrown to sea.

Robert flees Constantinople following the attack, seeking the assistance of Pope Gregory IX in reestablishing his authority.

One of Tsar Ivan's daughters is married to the Serbian prince Stefan Vladislav of the Nemanjic Dynasty, whom Ivan is able to establish as king of Serbia; another is married to Manuel Angelos, ruler of Salonika; and his third daughter, Helen, is betrothed in 1228 to the eleven-year-old emperor Baldwin II.

John III, emperor at Nicaea and regent for young Baldwin II, his grandson, seeks to retake Constantinople from the Latins before his rivals Theodore Angelus Doukas, despot of Epirus, or Ivan Asen II, Tsar of Bulgaria.

The despots of Epirus and Thessaly, who had saved much of northern Greece from Western conquest after 1204, are direct descendants of Constantine Angelos and Theodora, daughter of Emperor Alexios I Komnenos.

Theodore Komnenos Doukas, who had earlier seized Thessalonica and been crowned emperor there, marches on Constantinople, but his rivals, the Nicaean emperor and the Bulgarian tsar, attack him from the east and north.