ɪnðə bɪɡˈɪnɪŋ ʌvðɪ ɪlˈɛvənθ sˈɛntʃɚɹi, ðɪ ˈɛɹiə wˌɪtʃ lˈeɪɾɚ bɪkˌeɪm ðə θˈiːm ʌv sˈɜːmiəm lˈeɪ wɪðˌɪn ðə bˈoːɹdɚz ʌvðə fˈɜːst bʌlɡˈɛɹiən ˈɛmpaɪɚ, ˌʌndɚ tsˈɑːɹ sˈæmjuːˌɪl ænd ðə lˈoʊkəl dˈuːk vˈɔɪvoʊd nˈoʊn æz sˈɜːmən ɹˈuːld ˌoʊvɚ sˈɜːmiəm ænd sɚɹˈaʊndɪŋ ˈɛɹiə.
In the beginning of the 11th century, the area which later became the Theme of Sirmium lay within the borders of the First Bulgarian Empire, under Tsar Samuil and the local duke (voivode) known as Sermon ruled over Sirmium and surrounding area.