This is a wide time span. From a Nordic perspective it spans the time from the Vikings and more or less the next 400 years. Lots of things had happen during this period, the foundation of the three Nordic countries, the Swedish "crusades" to Finland and the Danish to Estonia. Later on there was the forming of "the Kalmar union" a united Scandinavia under Danish leadership... and the constant Swedish rebellions (why do we always have a problem to accept unions?). These rebellions has actually served as a starting point for the forming of a Swedish identity.
In 1521 the final uprising against the Danish king started. This year is also the last time that a military operation took place in my home town Uppsala.
The year before, on the 6 of April 1520, a large battle was fought right here in the centre of the city. The battle is known as the "Good-Friday battle".
More info on the "Good Friday battle" when I have the time to translate it.