Crop failure!

The harvest begins, but soon your serfs return and report your worst fear... The crops failed to grow well enough and some disease weakened them even further! Finally a great wave of locusts have arrived and finished off most of the crop fields! There isn't much to bring in, and your people start to worry for their lives... What will become of them without food? They might manage to have enough to eat, but only if they won't have to pay taxes to you... But even with having them pay their ordinary taxes, you are losing a lot of money... 500 gold is all they can pay you from their share without risking famine.

Some serfs come to you, asking for your empathy and to exempt your people from this year's taxes... Or at least lower the taxes...