Editing Theodore II Laskaris (section)

===Towards sole rule===

Vatatzes was making preparations for a new attack on Constantinople in the spring of 1252, but the ruler of Epirus, [[Michael&nbsp;II Komnenos Doukas]] ({{reign|1230|1266/68}}), invaded Nicaean territory in Macedonia. Vatatzes appointed Theodore his viceroy in Asia Minor and launched a counter-attack against Michael&nbsp;II, forcing him to return to Epirus. Elena of Bulgaria died unexpectedly of unknown causes before the end of August. Theodore mourned his wife for more than the customary forty days. He abandoned fasting and wearing black only on his father's command. His wife's death intensified Theodore's melancholy. He secluded himself in the palace and dedicated his time to philosophical studies and writing. He only resumed his regular visits to the towns of Asia Minor in 1253.{{sfn|Angelov|2019|pp=92, 128–132}}{{sfn|Fine|2009|p=158}}

Early in 1253, Emperor Frederick&nbsp;II's son and successor, [[Conrad IV of Germany|Conrad]] ({{reign|1250|1254}}), forced most relatives of his father's mistress, [[Bianca Lancia]], into exile. They fled to Nicaea and sought asylum from Bianca's daughter, Empress Constanza-Anna. Since his father was staying in Thrace, the exiles were received by Theodore. Conrad changed his mind and sent the erudite [[Berthold of Hohenburg]], an in-law of the Lancias, to Nicaea to begin negotiations with them. While waiting for his father's return from Thrace, Theodore had philosophical conversations with Hohenburg. The study of ancient Greek philosophers had intensified in Europe, and Hohenburg asked Theodore for Greek philosophical works. This request reinforced Theodore's pride in the Greeks' ancient heritage, and he decided to publish his own works.{{sfn|Angelov|2019|pp=140–145}}

Vatatzes returned to Nicaea in the winter of 1253. Early in 1254, he fell ill suddenly and never fully recovered. His illness made Theodore the actual ruler of the empire. Vatatzes was still alive when news of the Mongols' preparations for a new invasion of Asia Minor reached Nicaea.{{sfn|Angelov|2019|pp=147–148}}