A ranar 25 ga Mayu 717, Leo III ɗan Isaurian ya zama Sarkin Byzantium.A lokacin bazara na wannan shekarar Larabawa , karkashin jagorancin Maslama ibn Abd al-Malik, suka ketare Dardanelles suka kewaye Konstantinoful tare da babban sojoji da sojojin ruwa.Leo III ya roki Tervel don neman taimako, yana dogara ga yarjejeniyar 716, kuma Tervel ya amince.Rikicin farko da aka yi tsakanin ’yan kabilar Bulgar da Larabawa ya kare da samun nasara a kan Bulgar.A cikin matakin farko na wannan kawanya, 'yan Bulgar sun bayyana a bayan musulmi kuma an lalata yawancin sojojinsu, sauran kuma sun makale.Larabawa sun gina ramuka biyu a kusa da sansaninsu da ke fuskantar sojojin Bulgaria da katangar birnin.Sun dage tare da kewaye duk da tsananin sanyi tare da dusar ƙanƙara kwanaki 100.A cikin bazara, sojojin ruwa na Rumawa sun lalata jiragen ruwa na Larabawa da suka zo da sabbin kayayyaki da kayan aiki, yayin da sojojin Rumawa suka fatattaki sojojin Larabawa a Bitiniya.A ƙarshe, a farkon lokacin rani Larabawa sun yi yaƙi da Bulgars amma sun sha kashi sosai.A cewar Theophanes the Confessor, Bulgars sun kashe wasu Larabawa kusan 22,000 a yakin.Ba da jimawa ba, Larabawa sun tayar da kewaye.Yawancin masana tarihi sun danganta nasarar Byzantine-Bulgaria tare da dakatar da hare-haren Larabawa a kan Turai.