Publius Aelius Hadrianus was born in AD 76 at Italica in southern Spain. Orphaned at the age of ten, he was brought up by his father's cousin, the future Emperor Trajan. Hadrian later married Trajan's niece's daughter, and wrote speeches for his guardian when Trajan became emperor. Yet the two men were never close. It was only on Trajan's deathbed that he adopted Hadrian as his son and successor.

After rising through the ranks of the army, Hadrian served as governor of Pannonia and Syria where, in AD 117, he heard the news of Trajan's death and his own adoption. This was a troubled time, as many of the nations recently conquered by Trajan were rising in rebellion. Hadrian, believing that the empire had grown too large to be properly defended, gave up some of Trajan's conquests in the Balkans and Mesopotamia (Iraq), and set about building new strong defences. Hadrian's Wall was just one of many defensive works he constructed. Others followed natural barriers such as the Rhine and the Danube.

Hadrian was highly educated and loved Greek culture so much that, as a young man, he had been nicknamed the "Greekling". He was the first Roman emperor to grow a beard - a sign of his admiration for the famous Greek philosophers such as Socrates and Plato, who were bearded. Hadrian began a fashion for beards which lasted until the fourth century.

Memory man

The emperor was famous for his amazing memory, which meant that he never forgot a face or a name. He astounded visitors with his ability to hold conversations, while writing and dictating letters at the same time. He also found time to paint, and was a skilled architect with a fondness for domes - a taste which had been criticised by Trajan's official architect, Apollodorus, who described Hadrian's domes as ''pumpkins''. It was Hadrian who built the famous domed temple, the Pantheon, in Rome.

No emperor travelled more widely than Hadrian, who spent the years between AD 121-125 and 128-134 moving around the empire with his court. His main reason for travelling was to strengthen the frontiers, though he was also motivated by sheer curiosity. In Sicily, for example, he climbed Mount Etna to see the sunrise, which was said to be coloured like a rainbow.

Hadrian had a wife, Sabina, but they loathed each other. The great love of his life was a Greek youth called Antinous, who drowned in the Nile in AD 130 while the emperor was visiting Egypt. Hadrian was so devastated by this death that he declared that Antinous was now a god, and founded a city, Antinopolis, in his honour. 

Hadrian wrote an autobiography, now lost, and a number of poems. The most famous of these, written shortly before his death in AD 138, was addressed to his soul:

Animula vagula blandula
Hospes comesque corporis
Quae nunc abibis in loca
Pallidula rigida nudula
Nec ut soles dabis iocos

Little wandering soul,
Body's guest and companion,
What place are you going to now?
Somewhere cold dark and gloomy,
Never again to joke or play.