Attila more frequently referred to as Attila the Hun, was the ruler of the Huns

Huns

The Huns were a group of nomadic people who, appearing from east of the Volga River, migrated into Europe c. AD 370 and established the vast Hunnic Empire there. Since de Guignes linked them with the Xiongnu, who had been northern neighbours of China 300 years prior to the emergence of the Huns,...

 from 434 until his death in 453. He was leader of the Hunnic Empire

Hunnic Empire

The Hunnic Empire was an empire established by the Huns. The Huns were a confederation of Eurasian tribes from the steppes of Central Asia. Appearing from beyond the Volga River some years after the middle of the 4th century, they first overran the Alani, who occupied the plains between the Volga...

, which stretched from the Ural River

Ural River

The Ural or Jayıq/Zhayyq , known as Yaik before 1775, is a river flowing through Russia and Kazakhstan. It arises in the southern Ural Mountains and ends at the Caspian Sea. Its total length is 1,511 mi making it the third longest river in Europe after the Volga and the Danube...

 to the Rhine River and from the Danube River to the Baltic Sea

Baltic Sea

The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...

. During his reign he was one of the most feared enemies of the Western

Western Roman Empire

The Western Roman Empire was the western half of the Roman Empire after its division by Diocletian in 285; the other half of the Roman Empire was the Eastern Roman Empire, commonly referred to today as the Byzantine Empire....

 and Eastern Roman Empires. He crossed the Danube twice and plundered the Balkans

Balkans

The Balkans is a geopolitical and cultural region of southeastern Europe...

, but was unable to take Constantinople

Constantinople

Constantinople was the capital of the Roman, Eastern Roman, Byzantine, Latin, and Ottoman Empires. Throughout most of the Middle Ages, Constantinople was Europe's largest and wealthiest city.-Names:...

.