House 4 begins at the Imum Coeli (IC), the lowest point of the chart, opposite the Midheaven. It represents the inner world and foundations: family, childhood, home, origins, the feeling of inner security.
A planet in House 4 often influences your relationship to home and roots — in the literal sense (the house, the family) as much as the figurative sense (what anchors you inwardly).
Angular house (with Houses 1, 7, and 10): like the other three angles of the chart, House 4 is judged in classical doctrine among the strongest — a planet at the Imum Coeli acts with more force and visibility than elsewhere.
Natural sign and ruler: Cancer, ruler the Moon — consistent with the theme: Cancer is itself the sign most associated with home and family. See the Cancer entry.
No planet finds its joy in House 4 in the classical doctrine of the seven planetary joys (see House 1) — one angle out of four remains outside this scheme, which only covers 7 of the 12 houses.