Popish in a sentence as an adjective

English Catholics were popish spies who would try to blow up parliament and overthrow the government, etc.

Section 2 of the Act of Settlement 1701 explicitly bans Roman Catholics from inheriting the throne–"all and every person and persons, who shall or may take or inherit the said Crown, by virtue of the limitation of this present act, and is, are or shall be reconciled to, or shall hold communion with, the See or Church of Rome, or shall profess the popish religion, or shall marry a papist, shall be subject to such incapacities, as in such case or cases are by the said recited act provided, enacted, and established".

Popish definitions

adjective

of or relating to or supporting Romanism; "the Roman Catholic Church"

See also: Roman R.C. Romanist romish papist papistic papistical