The legend of 'Drake's Drum' says that if England is ever again in peril, the drum of Sir Francis Drake should be beaten and a grate wind will blow the invaders away.

another is of King Arthur, that if Britain faces defeat, King Arthur will rise from Avalon to lead his knights into battle once more.

The Hessian s believed that Charlemagne and his knights lay sleeping in Oldenburg, ready to wake when the Antichrist threatens Christendom.

The Spanish say that when the Moores invaded Spain, Saint James himself came to fight for them. they call him Matamoros, which means something along the lines of 'Moore killer'

Of course there was Lords Nelson and Wellington from the times of Napoleon and Sharpe and Hornblower from fiction.

hundreds from the world wars and since.

But who can say who the first one was, how far back do you go, to the Greeks and Romans, earlier than them?

i think you should re-categorize your question

Gilgamesh, known as Bilgameṣ in the earliest text, was the fifth king of Uruk (Early Dynastic II, first dynasty of Uruk), ruling circa 2700 BC, according to the Sumerian king list. According to the Tummal Inscription, Gilgamesh, and his son Urlugal, rebuilt the sanctuary of the goddess Ninlil, in Tummal, a sacred quarter in her city of Nippur. Gilgamesh is the central character in the Epic of Gilgamesh, the greatest surviving work of early Mesopotamian literature. In the epic his father was Lugalbanda and his mother was Ninsun (whom some call Rimat Ninsun), a goddess. Gilgamesh is described as two parts god and one part man.

In Mesopotamian mythology, Gilgamesh is credited with having been a demigod of superhuman strength who built a great city wall to defend his people from external threats and travelled to meet Utnapishtim, the sage who had survived the Great Deluge.

Think he was the first hero in history. Source Wikipedia