This thesis concerns itself primarily with relations between James I. Stuart and his Catholic subjects in England. More precisely with the timeframe from his ascension to the English throne in 1603. until his death in 1625. The thesis will also take in account formative years of James I. in Scotland, and the Elizabethan legacy of her relations with Catholics in England, in hopes of providing better insight into James's personal thoughts about Catholics, as well as the state of relations with English Catholics that James inherited from his predecessor upon ascension upon the English throne in 1603. One of the main goals of this thesis is to determine are there any changes in relations with Catholics in England upon James's ascension. To put it more concretely, are there any changes in the matters of toleration of English Catholics or decreased levels of religious persecution towards the said Catholics in contrast to the Elizabethan era. Second main goal is to determine changes in relations with Catholics in England during the reign of James I. from 1603. to 1625. The main tools of such an analysis will be ideological conflicts and similarities between ideologies of James I. and Catholics in England. The other method used for said analysis will be the effects of political events like the Gunpowder Plot or the prospect of the Spanish Match on relations between James I. and the Catholics. The general conclusion is that reign of king James I. was more tolerant towards the Catholics in England than his predecessor Elizabeth I.'s reign in England from 1558. to 1603. But toleration never reached its full extent because forms of religious persecution such as recusant fines or the Oath of Allegiance continued to exist. But toleration in full extent was practically impossible. The reason for such an impossibility lies in two things. The first is James's ambition in building the early modern form of absolute monarchy. And the second is political and religious context of that era in England.