[yzzxy]

    So. The Spear-Danes in days gone by
    and the kings who ruled them had courage and greatness.
    We have heard of those princes' heroic campaigns.

The first word of the first known English document is "so" in this style.

[lobster_johnson]

That's the Heaney translation. The original Old English starts this way:

> Hwæt! Wé Gárdena in géardagum

Hwæt has usually been translated as "listen", though it has since evolved into the modern word "what" and at least one researched thinks it is not an interjection but an intensifier [1]. In archaic English it might have been translated as "hark".

[1] http://www.independent.co.uk/arts-entertainment/books/news/l...