As Lord High Admiral of Scotland, Bothwell sailed around Europe. During a visit to Copenhagen around 1559, he fell in love with Anna Tronds, known in English as Anna Throndsen and posthumously as Anna Rustung. She was a Norwegian noblewoman whose father, Kristoffer Trondson (Rustung), a famous Norwegian admiral, was serving as Danish Royal Consul.
After their engagement, or more likely marriage under Norwegian law, Anna left with Bothwell. In Flanders, he said he was out of money and asked Anna to sell all her possessions. She complied and visited her family in Denmark to ask for more money. Anna was unhappy and apparently given to complaining about Bothwell.
Bothwell's treatment of Anna played a part in his eventual downfall.