Kaloyan ya kulla yarjejeniya da Theodore I Laskaris, Sarkin Nicaea .Laskaris ya fara yaƙi da David Komnenos, Sarkin Trebizond, wanda Latins ke goyon bayansa.Ya rinjayi Kaloyan ya mamaye Thrace, wanda ya tilasta Henry ya janye sojojinsa daga Asiya Ƙarama.Kaloyan ya kewaye Adrianople a cikin Afrilu 1207, ta yin amfani da tartsatsi, amma masu tsaron gida sun yi tsayayya.Bayan wata guda, Cumans suka yi watsi da sansanin Kaloyan, saboda suna so su koma cikin tsaunin Pontic, wanda ya tilasta Kaloyan ya ɗage kewayen.Innocent III ya bukaci Kaloyan ya yi sulhu da Latin, amma bai yi biyayya ba.Henry ya kammala sulhu da Laskaris a watan Yuli 1207. Ya kuma yi ganawa da Boniface na Tasalonika, wanda ya amince da kasancewarsa a Kypsela a Thrace.Koyaya, a hanyarsa ta komawa Tasalonika, Boniface an yi masa kwanton bauna aka kashe shi a Mosynopolis a ranar 4 ga Satumba.A cewar Geoffrey na Villehardouin 'yan kasar Bulgariya na gida ne suka aikata wannan aika-aika kuma sun aika kan Boniface zuwa Kaloyan.Robert na Clari da Choniates sun rubuta cewa Kaloyan ya shirya kwanton bauna.Boniface ya gaje shi da ƙaramin ɗansa, Demetrius.Mahaifiyar yaron, Margaret ta Hungary, ta dauki nauyin gudanar da mulkin.Kaloyan ya yi gaggawa zuwa Tasalonika kuma ya kewaye garin.Kaloyan ya mutu a lokacin da aka kewaye Tasalonika a watan Oktoba 1207, amma yanayin mutuwarsa ba shi da tabbas.