Short answers, pulled from the story.
Attila ruled the Huns from 434 until his death in early 453. He came to power jointly with his elder brother Bleda after the death of their uncle Rugila, inheriting rule over the united Hunnic tribes.
Most scholars trace the name to Gothic or Gepidic origin, formed from the noun atta meaning "father" and the diminutive suffix -ila, giving the meaning "little father." The Gothic etymology was first proposed by Jacob and Wilhelm Grimm in the early 19th century, and scholars such as Gerhard Doerfer describe it as simply correct Gothic.
Constantinople was protected by its double walls, which stopped the Hunnic army despite victories in the open field. Attila halted his Italian campaign at the River Po in 452 because of famine, disease in his army, a diplomatic intervention by Pope Leo I, and a Roman counterattack across the Danube that threatened his home territories.
Attila died in early 453 at a feast celebrating his marriage to a woman named Ildico. Priscus, writing from contemporary accounts, described severe internal bleeding with no external wound. A later account recorded by Marcellinus Comes claimed he was killed by his wife, but most historians prefer Priscus's account.
The empire collapsed within a year of Attila's death in 453. His three sons, Ellac, Dengizich, and Ernak, quarreled over the succession, prompting a Germanic revolt led by the Gepid ruler Ardaric. Ellac was killed at the Battle of Nedao in 454. The last Hunnic military campaign ended when Dengizich was killed by the general Anagast in 469.
The principal source is Priscus, a Byzantine diplomat who attended the Hunnic court in 449 as part of an embassy from Theodosius II and wrote a history covering 430 to 476. Jordanes, writing in the 6th century, cited Priscus extensively in The Origin and Deeds of the Goths. Ecclesiastical writings and medieval Germanic and Scandinavian literature preserve additional material, though it is often legendary.