Because the Church of England is the official church of Great Britain (which is one of the things America’s Founding Fathers did NOT want), the church is subject to the acts of the British Parliament. One of those was the Act of Uniformity passed on May 19, 1662. The Act stated every minister in England shall only use the official Book of Common Prayer and on August 24, 1662 the deadline arrived for all ministers to consent or face imprisonment. While it’s been modified over the years, the Act remains the law.