Theodor (wanda aka naɗa sarauta a ƙarƙashin sunan Bitrus) ya mai da shi mataimakinsa bayan da aka kashe Asen a shekara ta 1196. Bayan shekara guda, an kashe Theodor-Peter kuma Kaloyan ya zama sarkin Bulgeriya .Manufar fadada Kaloyan ta kawo shi cikin rikici da Daular Byzantine , Serbia da Hungary .Sarki Emeric na Hungary ya ba da izinin Paparoma wanda ya ba Kaloyan kambin sarauta ya shiga Bulgaria kawai bisa bukatar Paparoma.Kaloyan ya yi amfani da rugujewar daular Rumawa bayan faduwar Constantinople ga 'yan Salibiyya ko kuma " Latin " a shekara ta 1204. Ya kama kagara a Makidoniya da Thrace kuma ya goyi bayan tarzomar da jama'ar yankin suka yi a kan 'yan Salibiyya.Ya ci Baldwin I, Sarkin Latin na Konstantinoful, a yakin Adrianople a ranar 14 ga Afrilu 1205. An kama Baldwin;Ya rasu a gidan yarin Kaloyan.Kaloyan ya kaddamar da sabbin kamfen a kan 'Yan Salibiyya tare da kama ko lalata daruruwan katangarsu.Bayan haka, an san shi da Kaloyan mai kashe Romawa, domin sojojinsa sun kashe ko kuma kama dubban Romawa.