In Anglo-Saxon England, a "reeve" was an officer who was appointed by the king to be responsible for the public business of the locality. A high–ranking official, the "shire–reeve" (the precursor to the modern sheriff) was the representative of the royal authority in a "shire" or "county". The shire–reeve and his hundreds (deputies) wore a plate in the shape of a five, six, or seven point star made of brass, metal, or any other material that could be highly polished and visible by moonlight. This allowed them to identify each other, and over time, they began to put markings and insignias on the plates.
The seven point star is said to have been first used by the San Francisco Police Department. The seven points were decided on to represent the Seven Gifts of the Holy Spirit. Virtue, Divinity, Prudence, Fortitude, Honor, Glory and Praising God.
The seven–pointed star is worn over the left breast ostensibly implying that the star is meant to protect the most vulnerable part of the human body; the heart.