The Roman Catholic Church makes its first steps in North America when the colony ships "Dove" and "Ark" arrive in Maryland with 128 Catholic colonists. The members of this group had been chosen by Cecilius Calvert, second Lord Baltimore. The ships belonged to his father and the colony itself will be led by Leonard Calvert, Lord Baltimore's brother.
The purpose of the Maryland colony is to demonstrate that Catholics and Protestants can live together as equals. Cecilius Calvert is a convert to Catholicism and being Catholic is severely stigmatized in England at this time - especially for the nobility. Catholics are, in general, regarded as traitors and enemies, so it's fortunate that Lord Baltimore is granted any sort of charter at all.
The Maryland Charter establishes the colony as a palatinate, which means Baltimore and his descendants have very nearly the rights of an independent state rather than simply a colony. They can not only collect taxes and wage war, but they can even establish colonial nobility in Maryland.