This first major Byzantine expedition to the Morea is traditionally considered to have comprised two waves, one in autumn 1262 and one in the following spring. Michael VIII initially sent the
parakoimomenos John Makrenos to the Morea with 1,500 Turkish mercenaries and about 2,000 Anatolian Greeks, as well as with grants of privileges for the local potentates of Laconia, with the names localeft blank for Makrenos to fill. Upon his landing, people from
Tsakonia, the district of
Kinsterna, and the Slavs of
Mount Taygetos all flocked to enlist with the Byzantine commander. Makrenos reported back on the favourable conditions he found, and told Michael VIII that the entire peninsula was ripe for the taking with a few more men. The Emperor then sent his half-brother, the
sebastokrator Constantine Palaiologos, at the head of a further 1,000 men, and with more money, to the Morea. As part of their
treaty with Michael, and their traditional rivalry with the
Venetians, the
Genoese provided ships and crews to transport the Byzantines to the Morea, while the small Byzantine fleet was sent to harass the Latin island holdings in
Euboea and the
Cyclades. After arriving at Monemvasia, the
sebastokrator Constantine proceeded to cement and expand imperial authority in Laconia: he erected a number of forts to keep the Slavs of Taygetos in check, and then laid siege to Lacedaemon, while the imperial fleet seized the southern coasts of Laconia. The
Chronicle does not report on these events apart from the siege of Lacedaemon, but Pachymeres,
Nikephoros Gregoras, and Sanudo record that "daily clashes" took place with the Franks, and that several strongholds fell to the imperial troops; these are not named, but must have included the castles of Passavant, Geraki, and
Beaufort (Leuktron). By 1264, only Lacedaemon appears to have remained in Frankish hands in the region. In the meantime, William travelled to
Corinth to request the assistance of the other Latin princes of Greece. They, however, proved unwilling to come to his aid, all the while many of William's Greek subjects openly sided with the Byzantines. Constantine Palaiologos saw this as an opportunity to conquer William's principality outright. Abandoning the fruitless siege of Lacedaemon, he marched his army up the rivers
Eurotas and
Alfeios towards the Achaean capital,
Andravida, on the northwestern coast of the Morea. ==The battle==