Complex sentence: The fourth house, of which the cusp is often (but not always) the Imum Coeli, signifies a person's home, security, family, and those things in early life that served as a foundation for them.
Split into simpler sentences: The fourth house, of which the cusp is often (but not always) the Imum Coeli. It signifies a person's home, security, family, and those things in early life that served as a foundation for them.