Upon landing at the site of the new settlement, a ceremony was held to formally take possession of the land. In honor of his comrade, Louis (or his son, Jerome) Phélypeaux, Comte du Ponchartrain, Minister of Marine to Louis XIV, Cadillac named the settlement Fort Ponchartrain du Detroit.
Cadillac then marked village borders. The southern border was present day Jefferson Avenue. The northern border was between present day Larned Street and Jefferson Avenue. The eastern end was approximately where Griswold Street is today. And the western border was along present day Shelby Street. The area Cadillac marked off covered one square arpent (192.75 ft x 192.75 ft or 37,152.56 sq ft).
Building of the storehouse and stockade began immediately, however, the first building completed was Ste. Anne's Church. It is likely that the construction of Ste. Anne's started on July 26, the feast day of Ste. Anne. Two priests had accompanied Cadillac on his journey to the Detroit area, Father Constantin del Halle, a Recollet priest of the Franciscan order, and Father Francois Vaillant, a Jesuit priest. Father Vaillant, unhappy with Cadillac's apparent favoritism of the Franciscan order, his intentions to trade brandy to the Native Americans, and his encouraging of marriage between soldiers and Native American women, left the area almost immediately after the party landed. Thus Ste. Anne's followed the Franciscan order under the leadership of Father del Halle.