94 chapter three
the second advantage that the genoese could offer was their pre-
eminent position in the straits and the Black sea. Under the treaty
of nymphaion agreed with michael viii in 1261, the ligurian republic
became the naval guarantors of the Byzantine restoration, protecting it
above all from the warships of vengeful venice. the emperor repaid this
service with privileges, granting the genoese and their pisan allies the
sole and unconditional freedom to sail and trade within the Black sea.
the restrictive clause of the treaty imposed on them the obligation to
keep the venetians from the sea, who had dominated there from 1204
to 1261.148
the third inestimable part of the genoese contribution once they
took service with the sarai-cairo axis was that they had the political
will and the strength required to face disapproval and reprisals from the
powers of Western christendom: they took on an enormous risk when
they chose to enter the service of the mongol khan and the mamluk
sultan, the crusaders’ deadly enemies, and to defend the “schismatic”
Byzantine emperor against the latins, who were eager to return to
constantinople.149
it is true that when the genoese abandoned and betrayed the West-
ern world of which they had been part, they were (so to speak) helped
along by the venetians, who in 1258 had expelled them from acre, the
most significant european-held centre of levantine trade: the losses that
they suffered were sufficiently grave that they were forced to seek other
horizons to make good the deficit,150 just as would happen in 1291 to
those who had displaced them. this new opportunity was found in the
Black sea, and amply repaid the republic’s fundamental political choice
to tie their fortunes to the muslim great powers and to Byzantium.
despite all their subsequent difficulties, the genoese remained faithful to
148 the original greek text of the treaty of nymphaion is lost; among the best editions
of the latin copies, manfroni, “le relazioni,” pp. 791–809; some titles from the immense
bibliography on the treaty: heyd, Histoire, i, pp. 426–431; caro, Genua, i, pp. 36–79; chap-
man, Michel Paléologue, p. 42; Brătianu, Recherches, pp. 81–82; thiriet, Régestes, pp. 103–
104; geanakoplos, Emperor, pp. 81–91; ahrweiler, Byzance, pp. 329–330; Balard, Romanie, i,
pp. 42 ff.; papacostea, “tana,” passim.
149 the pressure which the citizens of the republic faced from 1261 onwards, when they
were excommunicated for the first time, did not persuade them to renounce their chosen
path (cf. canard, “Un traité,” p. 210–211; spuler, “außenpolitik,” p. 31).
150 for this event and its consequences see caro, Genua, i, pp. 36–79; Brătianu, Recher-
ches, p. 58; schmid, Beziehungen, p. 127; prawer, Histoire, ii, pp. 359–373; Balard, Romanie, i,
p. 42; papacostea, “gênes,” p. 215.