The middle ages covers a period of a thousand years – and yet much of its music-making is a mystery to us. We’re not completely in the dark, though, so the aim of this article is to give a broad beginner’s guide to the principles of secular medieval music. When were the middle ages? How do we know what the music sounded like? What were the earliest surviving songs? What was its dance music like? Why does medieval music sound so different to today’s? How did medieval musicians harmonise?