In medieval Sweden, all of these could actually be the same.

Swedish nobility was not officially instated until 1280, and while there were great men and landowners before that, a majority of the population belonged to a self-owning peasant family (around 60-65%). These people had the right to elect their King, only paid taxes as a fee to not go in ledung (ie paying the King to pay someone to take their place in a military campaign), had the right and were obligatyed by law to keep and train with arms.

The free-holding peasants were very defensive of these old rights and resented anyone who tried to limit or restrict them.

During the era of the Kalmar Union, the King was Danish, and from the Engelbrekt rebellion 1434 until the end of the Kalmar Union 1521 (and continued into the reign of Gustav Eriksson (Wasa), with several rebellions until the end of the Dacke feud 1534) Sweden was more or less in a constant civil war. Some noblemen and their clients and the peasants of areas where they held great influence would support the Danish King, while others would support native candidates. In the midst of this, the peasants rose several times.

Collecting tax from free-holding peasants was the duty of the local bailiff, who usually occupied the local castle or fort (not seldom a small wooden fort - strong castles were very rare in Sweden) with a meagre garrison.

Since the Danish King after the Engelbrekt rebellion 1434 needed to force the Swedes to elect him King of Sweden, he would usually come with a host of mercenaries, often Germans, sometimes Frisians, Scots or Dutch, but most often Germans and fight the rebellious noblemen who had raised an army by promising to protect the old rights of the peasants, who then duly rose and formed an army.

In open combat, the peasant militia often came up short against these mercenaries, such as Hans campaign to re-gain the throne of Sweden 1502, from which the excellent drawings of Paul Dolnstein, German mercenary engineer, of German Landsknechts in battle with Swedish peasant militia.

Still, with good leadership, superior numbers or ambushing the enemy in the deep forests of Sweden, the peasant militia could and would often win.

The mecenary armies deployed by the Danish Kings were usually rwarded by their officers being placed (as loyal subjects of the Danish King) as bailiffs in the Swedish provinces. The officers were usually Germans, and used to unarmed serfs without rights on the continent. Usually, there was an unofficial agreement between the King and these mercenary officers that anything they could collect above what was due to the crown, they could keep. Thus they often used brutal methods to extract extra taxes from the peasants - who duly revolted, killed the bailiff and burned his fort or castle.

Some local nobleman would then harness this sudden uprising to further his own ambitions and usually depose the King.

So, the tax collector, the nobleman and the foreigner were often the same person in medieval Sweden. If he respected the old rights of the peasants, he would usually be respected. If he did not, he would pretty soon face a rebellion.