The raids launched in the two years since Harun al-Rashid's accession in 786 have been relatively minor affairs; the first great invasion of the new reign occurs in 788, when a large expeditionary force crosses the Cilician Gates into the Anatolic Theme.

The raid is not mentioned in Arabic sources, but its description by the Byzantine chronicler Theophanes the Confessor points to a major invasion, as it is confronted by the forces of the two most powerful imperial thematic armies, those of the Anatolic Theme itself and of the Opsician Theme.

The site of the battle is called "Kopidnadon" in Theophanes, a name otherwise unattested.

Modern scholars, beginning with Henri Grégoire in 1932, have identified it with the town of Podandos, on the western exit of the Cilician Gates.

According to the brief account of Theophanes, the battle ended in a bloody defeat for the Byzantines, who lost many men and officers, including members of the tagma of the Scholai who had been banished to the provinces by Irene in 786 for their continued support of Iconoclasm.

Theophanes also singles out the loss of the capable officer Diogenes, a tourmarches (division commander) of the Anatolics.

The immediate impact of the imperial defeat seems to have been negligible; losses were heavy but not unbearable, and the level of devastation of the region seems to have been minimal.

In material terms, there is therefore little to distinguish the defeat at Kopidnadon from the "typical" Arab raid.

It marks, however, a recommencement of large-scale border warfare after the relative lull since 782, which will continue unabated until Harun's death in 809 and the subsequent Abbasid civil war.