The Byzantine Empire.
The eastern half of the old Roman empire.
The Byzantine Empire lasted around 1000 after being started around 330 AD when the Roman Emperor Constantine adopted the city of Byzantium as his seat of power, renaming it Constantinople.
The Byzantine empire was located in the eastern half of the old roman empire but was very different than the older empire. The Religion, Language, level of learning changed. The language switched from Latin,like the old roman empire, to Greek. The Religion, though it stayed christian, switched from Roman Catholic to Greek Orthodox. The Roman empire fell into the dark ages where almost all learning came to a halt while the byzantine empire still held onto and preserved the Greek and Roman culture of knowledge,art,and ideas.
The Byzantine empire was very influential, specifically to Russia. Often the Byzantine ideas and beliefs were introduced into Russia through trade. The Byzantine empire influenced the religion, writing, art and architecture of Russia.The Russians received the religion of Greek Orthodox which even eventually became Russian orthodox. The Russians received the Cyrillic alphabet, that they still use today, from the Byzantines. The style of art the Byzantines are famous for are mosaics. Mosaics are pictures or patterns produced by arranging together small colored pieces of hard material, such as stone, tile, or glass. The Byzantines influenced the Russians to start using this style of art.