(i) St. Sophia Cathedral was built in mid-sixth century AD (CE).
(ii) It was the most magnificent building in Europe.
(iii) It was known for its innovative architectural techniques.
(iv) This Cathedral was turned into a mosque by the Ottoman Turks when they captured Constantinople.

(i) Han Empire once again threw open the silk road for trade.
(ii) A large export trade, mainly in silk, reached as far as the Roman Empire.
(iii) In the north artisans and herders of rival "barbarian" dynasties brought in new techniques like the methods of harnessing horses, use of saddle and stirrup.
(iv) Techniques of building bridges and mountain roads and seafaring.
(v) At the beginning of the Christian Era, the Han Empire rivalled that of Roman in size and Wealth.

(i) Carthage sent a general named Hannibal.
(ii) He defeated the Roman army and made a great part of Italy a desert.
(iii) In the second Punic War, Fabius confronted Hannibal and defeated him in the Battle of Zama.
(iv) Pursued by the Roman army, Hannibal ended his life by poisoning himself.

(i) Romans were prepared to tolerate Christianity. But the refusal of the Christians to pay respect to the Emperor's image was viewed as political treason.
(ii) It led to the prosecution of Christians.
(iii) Later one of the Roman Emperors, Constantine himself became a Christian. Christianity thus became the official religion of the Empire.

(i) Prisoners of war were enslaved in Rome.
(ii) Big landlords bought slaves cheaply and used them to cultivate their estate.
(iii) The slave population grew and by the 1^st century BC(BCE) there were two million.
(iv) Slave labour led to the impoverishment of free labour.
(v) Many poor peasants had to abandon their children who also ended up in the slave markets.