What the First House governs
The First House is the most personal ground of the chart: the self as a living organism. It describes the physical body and constitution, the temperament, the outward appearance, and — above all — the manner in which a person approaches and is met by the world. Its cusp is the Ascendant, the degree rising on the eastern horizon at birth, which sets the entire house framework in motion.
As the first of the four angular houses, it is a place of great strength and visibility: planets here are worn openly and colour the whole personality.
The First House in the birth chart
The sign on the First-House cusp (the rising sign) and its ruler describe the persona — the instinctive style through which everything else is expressed. Planets tenanted in the First House are pushed to the front of the character; a person can rarely hide them. An empty First House is normal and simply directs attention to the Ascendant ruler wherever it sits.
The First / Seventh axis
The First House does not stand alone: it forms the horizon axis with the opposite Seventh House of partnership. Self and other define each other across this line. A strongly tenanted First often needs to learn relationship; a strongly tenanted Seventh often needs to reclaim the self. Read the two together.