1. The Florentine family of the Acciaioli in Greece

The Acciaioli (alternate spellings: Acciaiuoli and Acciajuoli) was a powerful banking family from Florence which, at times, funded the lucrative military operations of the clashing ruling houses of northern Italy and Sicily and the titular pretenders to the Latin possessions in the Peloponnese. An eminent member of the Florentine family, Niccoló Acciaioli, moved to the Peloponnese when in the mid-14th century he acquired fiefs there, mainly in Elis and Messenia, as repayment for debts incurred by some of his clients. Yet the most important acquisition for this banker was the castellany of Corinth, which he received from Robert II of the Valois in 1358.

Later on, his nephew and heir Nerio, through purchases and warfare, gradually expanded his small kingdom as far as Argos and Vostitsa (1364). Thus, in the second half of the 14th century a new hereditary Latin hegemony was established in north-western Peloponnese, lacking any demographic or military underpinnings. In 1374, however, he clashed with the Catalans of Attica and Boeotia and managed to wrest the city of Megara from them. Naturally, to fend off these dangerous neighbours Nerio hired the services of the already infamous Navarrese Company, which had for long been active in the Peloponnese. Now the earlier (Catalan) and the more recent (Navarrese) Spanish mercenaries were ready to join battle in the Duchy of Attica and Boeotia.

2. The situation in the Catalan Duchy and Boeotia in the 1370s

By the mid-1360s the Catalans of the Duchy of Athens and Thebes had dwindled in numbers and were diplomatically isolated. The coup of the vicar general Roger de Lauria (alternate spelling: Lloria) at Thebes and the billeting of Turkmen (or Ottoman) mercenaries within the city could be construed as indications of civil strife and military decline. Their piratical raids had also waned, and therefore their income, too. Now they cooperated with the Pope to deal with the overriding threat of the Ottomans, although the Pope's plans for hosting a crusaders' council in Thebes in 1373 came to nothing. Their overlord from the Sicilian kingdom, Frederic III, was unable to aid the Company, who went in search of another protector in the face of the king of Aragon, Peter IV. The Acciaioli from Megaris certainly posed a threat. Thus, the duchy was floundering.

3. The critical biennium of 1379-1380

This biennium was to prove critical for Boeotia, for within one and a half years approximately -from the mid-1379 to till late in 1380- the region changed hands and paid the cost: its cities and its countryside were pillaged and its settlements were depopulated.

The events of the years 1379-1380 in this region can only be reconstructed tentatively and in broad lines: Nerio Acciaioli from Megara monitored the situation in neighbouring Boeotia, and at the same time he came into contact with Francisco Giorgio Pallavicini, the marquis of Vodonitsa, and Nicola dalle Carceri, the terziere of Venetian Euboea. Having secured their goodwill, Nerio decided to hire (1378) a contingent of the Navarrese Company with the aim of attacking Catalan Boeotia.

3.1. The capture of Thebes

Indeed, in March 1379, a contingent of this famous mercenary Company, funded by Nerio Acciaioli, set of from their base, Navarino, marched through north-western Peloponnese, crossed the Isthmus and Megaris and suddenly appeared before the weak walls of Thebes; they totalled approximately 400 men. Their leader was Juan de Urtubia, a mercenary serving Nerio for the second consecutive year. Following a short but violent attack, the city fell to the hands of the Navarrese, while its Catalan defenders, as well as those who had come to their aid from Athens, were slaughtered or captured. Those who could escaped to Venetian Euboea, while the rest remained and accepted the new status quo. Naturally, the Navarrese pillaged the city to complement their salary.

The fall of Thebes brought great sadness and anger to its overlord, Peter IV. The city's Latin archbishop, Simone Atumano, of Greek descent, was accused of being instrumental to this treason. Much later sources claim he invited the enemy to capture the city. According to this account, the Pope was asked to remove him because of his treason. The accusations against Atumano seem unfounded, however, for the Pope did not remove the archbishop or transfer him to another post.

3.2. The capture of Lebadea

The castle of Lebadea suffered a similar fate around the end of the following year (1380). In this case, however, the Catalans managed to defend the city valiantly, but they were undermined by certain 'traitors' as the sources describe them. The castellan and governor of the city, Guillelmo de Almenara, was killed, while many Greeks and Catalans managed to flee to the nearby town of Salona. The Navarrese also tried to capture the castle of Steiris, but they were thwarted by the vigorous resistance of another mercenary group, composed of Albanians under the leadership of a certain Dimitri.

4. Epilogue

By 1381 Thebes, Lebadea and certainly a large part of the agricultural hinterland controlled by these cities, in other words the entire region of Boeotia had come under the control of the Florentine family of the Acciaioli. Thus their possessions were unified into one region stretching from Corinth to Megara and Lebadea. Athens was captured in 1388, and Nerio received the title 'Neri Acciaioli, signor di Corinto et del ducato di Athene'.