This brief story from Orkneyinga saga, the twelfth-century history of the Earls of Orkney, is chiefly of importance to me because it shows that medieval Englishmen were praying to a Norse saint. I can't make up my mind whether, as miracle-stories go, it's slightly odd or rather touching. The St Magnus in question is the martyred earl of Orkney Magnus Erlendsson (d.1116/7).
'In England, there were once two men staking money heavily on a game of dice. One of them had lost a great deal, and at last he staked a cargo-boat and everything else that he had, against all that he had lost. The other man was first to throw and got two sixes. The man we are speaking of thought this looked very bad for him, so he made a vow to St Magnus the Earl asking him not to let him lose all his possessions. Then he threw the dice. One of the dice broke and he got two sixes and an ace, so that he won everything at stake; and some time later he gave a lot of money to St Magnus.'