Final answer:
After Constantinople became the capital, the Eastern Roman Empire, or Byzantine Empire, centered on Greek culture, Orthodox Christianity, and maintained a stable and urban society, while the Western Roman Empire fragmented, spoke Latin with local dialects, and was dominated by smaller, rural administrations.
Step-by-step explanation:
The major differences between the Eastern and Western parts of the Roman Empire after Constantinople became the capital are rooted in geography, language, religion, and culture.
After Emperor Constantine moved his government there in 330 CE, Constantinople's strategic location controlled the Bosphorus and Dardanelles straits, making it a bustling gateway between Europe and Asia, and establishing the city as a hub for trade and military campaigns.
The Eastern Roman Empire, also known as the Byzantine Empire, saw Greek as the predominant language, different from the West where Latin was initially used by the church and elites, with local languages prevailing in everyday use. The division in the Christian church into Western Catholics and Eastern Orthodox Christians after 1000 CE further emphasized the cultural and religious split.
Additionally, while the West experienced fragmentation into various small kingdoms and governmental entities, the East maintained a degree of continuity and stability, retaining Roman traditions and structures.
Lastly, the Byzantine Empire continued to thrive for nearly another 1000 years after the fall of Rome, spreading Greek language and Christianity across its territories, a legacy still evident in the use of the Cyrillic alphabet by certain Eastern European countries. Meanwhile, the Western Roman Empire fragmented and was characterized by smaller political units and a decline in urban centers.