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.

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.

…the nobles are taken to Tarnovo.

His fame for being a merciful and just ruler goes ahead of his march to the lands of Theodore Komnenos and they are regained to Bulgaria without resistance.

After defeating Theodore, Ivan acquires large parts of Albania, Serbia, Macedonia, and Epirus. (The record of his achievements, dated 1230, can still be seen in the old Church of the Forty Martyrs at Turnovo.)

The regency of the Latin empire (i.e., of the Greek Empire of Constantinople now under crusader rule) is now offered to Ivan, who agrees in return to give back his conquests in Epirus, western Macedonia, and Albania.