Charles I summoned his Scottish estates three times before the Scottish revolution of 1638: in 1625, 1630 and 1633. This article examines the convention of estates of 1630, held one year after Charles had suspended his English parliament. Members of the convention agreed to renew the regular parliamentary taxation (though they refused to vote it for a longer period) and proved surprisingly co-operative over Charles's controversial revocation. However, there was a major explosion of opposition on religious grounds. Two presbyterian petitions attempted to sabotage the enforcement of the five articles of Perth, the crown's flagship liturgical policy; the petitions seemed likely to attract the support of a majority of the estates but were suppressed by high-handed government action. A resolution by the estates against the five articles of Perth might have had a similar effect to the House of Commons' resolutions of 1629 that led to the suspension of the English parliament. The article examines what is known about the dissidents and argues that continuity can be identified both with previous opponents of royal policy (notably in 1621) and with subsequent support for the National Covenant after 1638.