About 6.2 million total viewers watched the program in its 10 p.m. premiere time slot and 2.1 million more caught an encore showing.
Created and written by Michael Hirst, the series stars Travis Fimmel, Gabriel Byrne, Clive Standen, Katheryn Winnick, Jessalyn Gilsig and George Blagden.
"'Vikings' is an incredible win for History -- our first scripted series. We began this journey over six years ago, when we set sail to broaden the genre of History and now we are the only cable network to have achieved this amazing level of success in both non-fiction and scripted genres," Nancy Dubuc, president of entertainment and media for A+E Networks, said in a statement Monday.
"People think they know the Vikings -- but the reality is more complex. We knew our audience had an appetite for this unexpected storytelling and it was a big bet that paid off."