)what byzantine city was a wealthy center of trade that maintained the commercial links between europe and asia?

Constantinople

Explanation:

Constantinople was the capital city of the Byzantine Empire. It was founded by Emperor Constantine in 324 AD, in fact, Constantinople means "City of Constantine." It was founded over the ancient city of Byzantium and today it is known as Istanbul. Constantinople, due to its strategical position as a natural link between East and West, became one of the wealthiest and most important cities in the Mediterranean Sea. Constantinople is a bi-continental city because it extends in two continents: Europe and Asia. At the time of the Byzantine Empire, it was one of the most relevant nodes of trade that connected the Silk Road with the West, bringing products from China to the markets of Europe, the Middle East, and North Africa.

what are the others?

soviet influence spread across eastern europe sharply during and after wwii. the soviet armies liberated the countries in eastern europe and occupied them from the germans as they were forced to retreat towards germany.