Which development is most closely associated
with the beginning of the byzantine empire?
(1) emergence of the russian orthodox church
(2) division of the roman empire
(3) building of the hagia sophia
(4) fall of constantinople

The develompent that is most closely associated with the beginning of the Byzantine Empire was the division of the Roman Empire (2). 

The reason why this is the correct answer is because during the divison, the Western and Eastern (which was later known as the Byzantine empire) Roman Empire was founded. 

Bis your correct answer