ANSWERS
Byzantine Empire: Justinian, Cyrillic alphabet, dependent on trade.
Roman Empire: Augustus, Latin as main language, dependent on trade.
Roman Empire
The Roman Empire began when Augustus Caesar (27 BCE-14 CE) became the first emperor of Rome. His ruled until his death in A.D. 14.
The Empire ended in 476 CE. But continued as the Byzantine Empire in the East.
While the Empire reigned, the trade was essential to their economy. They traded a vast variety of items including beef, corn, glassware, iron, lead, leather, marble, olive oil, perfumes, purple dye, silk, silver, spices, timber, tin and wine.
Latin was their original language, and along with Greek, they both were the official languages.
Byzantine Empire
The Economy of Byzantine Empire (330 A.D - 1453) was based on trade too, its favorable location on the European side of the Bosporus (the part linking the Black Sea to the Mediterranean), gave it the advantage to serve as a transit and trade point between Europe and Asia.
Some commodities traded were grain, silk, textiles in general, perfumes, timber and wax, ceramics, spices, oil, wine, salt, fish, meat and slaves.
The majority of its population were Roman and Christians that spoke Greek.
Justinian I was one of the outstanding rulers of the Empire, he governed from 527 until he died in 565. During his reign, he expanded the Empire, many great monuments were built including the famous Hagia Sophia, reformed the law and helped shape the modern concept of the state.
The Cyrillic alphabet was developed during the 9th century AD by Cyril and Methodius ( two Byzantine brothers who were Christian theologians and Christian missionaries). This writing system later became the basis of alphabets used in parts of Southeastern Europe and Northern Eurasia.