He allowed the fleet, which his father had organized, to fall into decay; and the empire was thus less able than ever to resist the exacting demands of the rival powers of Venice and Genoa.
During his reign the Ottoman Turks under Osman conquered nearly the whole of Bithynia; and to resist them the emperor called in the aid of the Catalan Roger de Flor, who commanded a body of Aragonese and Catalan adventurers known as Almogavars. The Turks were defeated, but Roger was found to be nearly as formidable an enemy to the imperial power. He was assassinated by Andronicus's son and colleague (sometimes referred to as emperor Michael IX, though he never ruled in his own name), in 1305. His adventurers (known as the Catalan Grand Company or Companyia Catalana in Catalan) declared war upon Andronicus, and, after devastating Thrace and Macedonia, conquered the Duchy of Athens and Thebes.
In 1274 he married Anne of Hungary, a daughter of King Stephen V, with whom he had two sons:
- Michael IX Palaeologus
After she died in 1281 Andronicus married a daughter of Wilhelm IX of Montferrat, Yolande, who took the name of Irene and bore him:
- John (c. 1286 - 1308)
- Theodore I, Marquis of Montferrat (1291-1338)
- Demetrius (d. after 1343)
- Simonis (1294 - after 1336) (married King of Serbia Stephen II Urosh Milutin)
He also had at least two illegitimate daughters:
- Irene, wife of John II despot of Thessaly
- Maria, wife of Tokhta Khan of the Golden Horde