According to the Chronicle of the Morea, the Byzantine army marching on Andravida in the spring of 1263 was in good spirits. They were singing and dancing. They had every reason to be confident: the army was large, its commander was the emperor's own half-brother, and the Frankish capital lay within reach. What they apparently had not accounted for was John of Katavas — old, suffering from gout, commanding around 300 men, and waiting for them at a narrow defile near Prinitza.
The road to Prinitza began four years earlier, at the Battle of Pelagonia in 1259. Byzantine forces under Emperor Michael VIII Palaiologos dealt the Latin Principality of Achaea a catastrophic defeat, killing or capturing most of its nobility, including Prince William II of Villehardouin himself. To buy his freedom, William surrendered several fortresses in the southeastern Morea — including Monemvasia and Mystras — swore personal allegiance to Michael, and accepted the position of vassal, even becoming godfather to one of the emperor's sons. He was released in early 1262. The arrangement was always fragile. Michael regarded the ceded fortresses as a foothold from which to reclaim the entire Peloponnese. William, meanwhile, was already working with the Venetians and the Pope to counter Byzantine power and eventually reclaim Constantinople for the Latins. Pope Urban IV nullified William's oaths to Michael in the summer of 1262. The two sides were drifting back toward open conflict, and Michael moved first.
The first Byzantine expedition to the Morea came in waves beginning in autumn 1262. Michael VIII sent the court official John Makrenos with around 1,500 Turkish mercenaries and 2,000 Anatolian Greek troops, along with letters of privilege for local Laconian magnates — the names left blank for Makrenos to fill in as he saw fit. The reception was encouraging: communities in Tsakonia, the Kinsterna district, and the Slavs of Mount Taygetos all enlisted with the Byzantine commander. Makrenos reported back that the peninsula was ready to fall. The emperor responded by dispatching his half-brother, the sebastokrator Constantine Palaiologos, with a further 1,000 men and more money. Genoese ships transported the reinforcements, in keeping with the Genoese-Byzantine alliance and the Genoese rivalry with Venice. Constantine consolidated Byzantine authority in Laconia, built forts, laid siege to Lacedaemon (Sparta), and by 1264 had reduced most of Frankish Laconia. William, unable to get help from the other Latin princes of Greece, watched many of his own Greek subjects side with Constantinople. Constantine saw his opportunity and turned northwest, marching his army up the Eurotas and Alpheus rivers toward Andravida, the Achaean capital.
Andravida, with William absent seeking aid, was in the care of John of Katavas. The Chronicle of the Morea describes him as brave but elderly and incapacitated by gout. Hearing that the Byzantine army was approaching, Katavas took the 300 or so men available to him and marched out to meet it. The Chronicle gives the Byzantine force numbers ranging from fifteen to twenty thousand — figures modern scholars regard as wildly inflated; the actual number was certainly far smaller, probably a few thousand, though still substantially larger than the Frankish force. At a narrow pass at Prinitza, near the site of Ancient Olympia, Katavas launched a surprise attack on the column. The Byzantines, reportedly in a relaxed and celebratory mood, were not prepared for the assault. Many soldiers were killed in the initial attack; the rest scattered into the surrounding woods. Constantine Palaiologos escaped, barely, and retreated with the survivors to the safety of Mystras. Katavas did not pursue — a prudent decision, given his limited numbers — and returned to Andravida.
The story of Prinitza comes almost entirely from the Chronicle of the Morea, a medieval narrative written by and for the Frankish aristocracy of Greece. It is, as scholars note, deeply biased: Byzantine commanders are routinely depicted as cowardly and devious, Frankish knights as brave to the point of recklessness. The figures it gives for the Byzantine army are certainly exaggerated. The Venetian historian Marino Sanudo Torsello mentions a battle at a place he calls 'Brenizza,' but conflates it with the following year's campaign. Byzantine sources say almost nothing about events in the Morea. What can be said with confidence is that a Byzantine advance on Andravida was halted in 1263, that Constantine Palaiologos retreated, and that the principality survived. The following year, Constantine returned, but his Turkish mercenaries defected to the Achaeans over unpaid wages. William attacked and won again at the Battle of Makryplagi. Together, the two battles secured Latin rule over the Morea for another generation.
The Battle of Prinitza took place at approximately 37.67°N, 21.50°E, near the site of Ancient Olympia in the Alpheus River valley. The narrow defile at Prinitza where the battle occurred is in the valley of the Alpheus as it runs westward toward the Ionian coast. From the air, the Alpheus River valley is clearly visible, bounded by the hills of Arcadia to the north and east. The ancient site of Olympia — with the Kronos Hill rising above the sanctuary precinct — provides the closest visual landmark. The nearest major airport is LGRX (Araxos), approximately 55 kilometers to the northwest, with the Alpheus valley providing a natural navigation corridor between the airport and the battle site.