Original: In late Roman times , the provincial boundaries were reorganized to form the Diocese of Macedonia , consisting of most of modern mainland Greece right across the Aegean to include Crete , southern Albania , and parts of modern-day Bulgaria and the Republic of Macedonia .
Simplified: Blagoevgrad Province ( Bulgarian : , oblast Blagoevgrad or , Blagoevgradska oblast ) , also known as Pirin Macedonia ( Bulgarian : , Pirinska Makedoniya ) , is a province ( oblast ) of southwestern Bulgaria .