Complex sentence: The monarchy returned in 1660, but the Civil War established the precedent that an English monarch cannot govern without the consent of Parliament, although this concept became legally established only as part of the Glorious Revolution of 1688.
Split into simpler sentences: The monarchy returned in 1660, but the Civil War had established the precedent that an English monarch cannot govern without the consent of Parliament. This concept became legally established as part of the Glorious Revolution of 1688.