Kammala jumla mai zuwa: A ƙarni na 6 da 7, garin Roman ya zama batun ƙaura na Slavic. Strymonites, ƙabilar Slavene, sun ɗauki sunansu daga kogin Strymon (Struma). Strymonites sun kasance masu zaman kansu har zuwa karni na 9, wanda ya biyo bayan Byzantine. Daga baya, yankin Strumica ya ci nasara da Bulgarian Khan Presian (836-852). Yankin Strumica ya kasance wani ɓangare na jihar Bulgaria tsawon shekaru sama da 150 har zuwa 1014, lokacin da aka sake shi.
Byzantines sun sake kama shi. A cikin karni na 11, rubuce-rubucen rubuce-rubuce sun fara komawa zuwa garin tare da sunan Slavic a matsayin "Strumica".