Oratorium, sc. templum, a place of prayer, comes the use of the word for a small chapel or place of prayer for the use of private individuals, generally attached to a mansion and sometimes to a church.
(b) Secondly, in war and peace Rome formed relations with her neighbours of Latium, and, as a sign of the Latin league which resulted, the cult of Diana was brought from Aricia and established on the Aventine in the "commune Latinorum Dianae templum" (Varro, Ling.
It was the duty of the augur, before the auspices properly so called (those from the sky and from birds) were taken, to mark out with his staff the templum or consecrated space within which his observations were intended to be made.
After prayer and sacrifice, he marked out the templum both in the sky and on the ground and dedicated it.