If we are talking about conquering the UK, I seem to remember that the last time a foreign army crossed the channel to successfully overthrow the government of England, it was a Dutch army (in 1688), and the Dutch king/stadholder that ascended to the throne proceeded also to "pacify" Ireland (something that has led to centuries of strife and bloodshed, at least up til a few days ago).
So being from mixed Dutch-Scandinavian descent, my ancestors have a history of conquering Britain