Genoa da Pisa sun zama jihohin da ke da haƙƙin ciniki a cikin Bahar Maliya.A cikin wannan karnin Jamhuriyar ta mamaye yankuna da yawa a cikin Crimea, inda aka kafa yankin Caffa na Genoese.Haɗin kai tare da daular Byzantine da aka maido ya ƙara arziƙi da ƙarfin Genoa, kuma a lokaci guda ya rage kasuwancin Venetian da Pisan.Daular Byzantine ta bai wa Genoa yawancin haƙƙin ciniki kyauta.A cikin 1282 Pisa ya yi ƙoƙari ya sami iko da kasuwanci da gudanarwa na Corsica, bayan da alkali Sinusello ya yi kira ga goyon baya da ya yi wa Genoa tawaye.A watan Agustan 1282, wani ɓangare na jiragen ruwa na Genoese sun tare kasuwancin Pisan kusa da kogin Arno.A lokacin 1283 duka Genoa da Pisa sun yi shirye-shiryen yaƙi.Genoa ta gina manyan jiragen ruwa 120, 60 daga cikinsu na Jamhuriya ne, yayin da sauran 60 ɗin aka yi hayar ga daidaikun mutane.Sama da sojojin haya 15,000 ne aka yi hayarsu a matsayin mahaya da sojoji.Rundunar Pisan ta kaucewa fada, kuma sun yi kokarin lalata jiragen ruwan Genoese a lokacin 1283. A ranar 5 ga Agusta, 1284, a yakin ruwa na Meloria, jiragen ruwa na Genoese, wanda ya ƙunshi jiragen ruwa 93 karkashin jagorancin Oberto Doria da Benedetto I Zaccaria, sun ci nasara da Pisan. , wanda ya ƙunshi jiragen ruwa 72 kuma Albertino Morosini da Ugolino della Gherardesca ne suka jagoranta.Genoa ta kama jiragen ruwa na Pisan guda 30, kuma ta nutse guda bakwai.Kimanin Pisans 8,000 aka kashe a lokacin yaƙin, fiye da rabin sojojin Pisan, waɗanda kusan 14,000 ne.Kashin Pisa, wanda bai taɓa samun cikakkiyar murmurewa a matsayin mai fafatawa a teku ba, ya haifar da samun nasarar sarrafa kasuwancin Corsica ta Genoa.Garin Sassari na Sardiniya, wanda ke karkashin ikon Pisan, ya zama gama gari ko kuma mai suna " gunduma mai 'yanci" wanda Genoa ke iko da shi.Sardinia, duk da haka, bai wuce zuwa Genoa na dindindin ba: sarakunan Aragonese na Naples sun yi jayayya game da iko kuma ba su tabbatar da shi ba har zuwa karni na sha biyar.