The revolution grow more violent mainly because radicals reacted to

Higher taxes.

Explanation:

The crown made acts which obligated people to pay more taxes and pay for the goods they were receiving from the Empire, but the Empire didn't pay for goods they sent to them. In addition to that, they were limited to make their own laws, because the crown feared their rebel, which happened anyways.

The revolution grow more violent mainly because radicals reacted to

prices rising to an all-time high.