<span>Hi there the only thing that remained of the Western Roman Empire was the Christian Church. The military was the only thing holding the country together at that point and it fell apart, losing everything save Northern France and Northwest Africa. The trade networks and the provincial elite were completely lost, leading to the Dark Ages of little economic growth and little to no cultural expression because it was actively repressed by anti-Roman sentiment.
The spread of Islam, from its heartland in the Middle East and North Africa to India and Southeast Asia, revealed the power of the religion and its commercial and sometimes military attributes.