The power structures in northern Baltic Europe in the Middle Ages can be studied through the correspondence between the Swedish authorities and the Hanseatic Councils. The letters were written in three languages: Latin, Low German and Swedish. Low German was the dominant language in the correspondence from the fifteenth century onwards. The aim of the paper is to examine the ways in which power relationships are manifested, including choice of language, conventional expressions of politeness, use of laudatory adjectives when addressing the recipient, use of adverbs to express deference or hedging, and elaborations in orthography.