Krum's dynasty (Bulgarian: Крумова династия) refers to the royal and later imperial family founded by the Khan of Bulgaria Krum (r. 803–814), producing the monarchs of First Bulgarian Empire between 803 and 991. During this period Bulgaria adopted Christianity, reached its greatest territorial extend and triggered a golden age of culture and literature. Under the patronage of these monarchs Bulgaria became the birthplace of the Cyrillic alphabet; Old Bulgarian became the lingua franca of much of Eastern Europe and it came to be known as Old Church Slavonic. As a result of the victory in the Byzantine–Bulgarian war of 913–927 the Byzantine Empire recognized the imperial title of the Bulgarian rulers and the Bulgarian Orthodox Church as an independent Patriarchate.