The blue banner bearing the motto "For Christ's Crown and Covenant" was first flown by the Scottish Covenanters in the 17th century and has been used by Reformed churches in North America since before the founding of the United States. To learn more about the Covenanters, a great start is The Scottish Covenanters by J.G. Vos.
High resolution files of the Blue Banner are available. Get the Blue Banner.