Theophilos is the son of the Emperor Michael II and his wife Thekla, and the godson of Emperor Leo V the Armenian.

Michael II had crowned Theophilos co-emperor in 822, shortly after his own accession.

Unlike his father, Theophilos had received an extensive education and showed interest in the arts.

He had succeeded his father as sole emperor on October 2, 829.

Theophilos continues in his predecessors' iconoclasm, though without his father's more conciliatory tone, issuing an edict in 832 forbidding the veneration of icons.

He also sees himself as the champion of justice, which he had served most ostentatiously by executing his father's co-conspirators against Leo V immediately after his accession.

At the time of his accession, Theophilos had been obliged to wage wars against the Arabs on two fronts.

Sicily was once again invaded by the Arabs, who took Palermo after a yearlong siege in 831, established the Emirate of Sicily, and gradually continued to expand across the island.

The imperial response to the invasion of Anatolia by the Abbasid Caliph Al-Ma'mun in 830 had been led by the Emperor himself, but the Empire had been defeated and had lost several fortresses.

In 831, Theophilos had retaliated by leading a large army into Cilicia and capturing Tarsus.

The Emperor had returned to Constantinople in triumph, but in the autumn he was defeated in Cappadocia.

Iconoclasm has been given full rein under Theophilos.

To weaken the political influence of Greek Orthodox monasticism, the Emperor and his former teacher John "the Grammarian", now patriarch of Constantinople as John VII, have mounted a persecution against the users of icons in Orthodox liturgy and devotion.

Support for Iconoclasm soon wanes, however, and the vast majority of the Greek Christians rally to the defense of their sacred art.

The cultural revival stimulated by Theophilos includes two significant advances in the area of classical studies: the gradual substitution of the minuscule, or smaller, cursive hand for the uncial, or larger, script, and the increase in the number of scriptoria, or copyists' workshops.

Theophilos has also restored the University of Constantinople after its eighth-century decline and appointed the brilliant teacher Leo the Mathematician as its new rector.

In the aftermath of the sack of Amorium, Theophilos had sought the aid of other powers against the Abbasid threat: embassies had been sent to both the western emperor Louis the Pious and to the court of Abd ar-Rahman II, Emir of Córdoba.

The imperial envoys had been received with honors, but no help has materialized.

The Abbasids, however, have not followed up on their success.

Warfare will continued between the two empires with raids and counter-raids for several years, but after a few imperial successes, a truce and prisoner exchange—which excludes the high-ranking captives from Amorium—is agreed in 841.