Final answer:
Charles I's need for funds for wars and his religious policies put him in constant struggle with Parliament, which opposed his attempts to impose taxes without consent and his perceived Catholic sympathies.
Step-by-step explanation:
Charles I was in constant struggle in the 1620s with Parliament, particularly due to issues around fiscal policy and religious stance. This tension escalated because of Charles I's need for funds to support wars, such as the war against Spain and his approach to governance without Parliament, which contributed to the outbreak of the English Civil War. His actions, like the attempt to impose taxes without Parliamentary consent and his perceived favor towards Catholicism, were met with strong opposition from Parliamentarians, especially the Puritans, who were influential in Parliament and opposed to Catholic practices.
The financial difficulties and governance issues of Charles I's reign compounded with the secret Treaty of Dover, where Charles II promised to convert to Catholicism in return for financial support from France, also led to anti-Catholic and anti-monarch sentiment. Ultimately, these actions resulted in fiscal chaos and a deeply divided kingdom.