Ramayana
ततो ऽस्तं भास्करे याते विसृज्य नृपवानरान् । सन्ध्यामुपास्य विधिवत्तदा नरवरोत्तमः । प्रवृत्तायां रजन्यां तु सो ऽन्तःपुरचरो ऽभवत् ॥ 7-36-63 ॥
Then, when the sun had set, having dismissed the kings and the vanaras and duly worshipped at the twilight juncture, that best among the foremost of men, when night had set in, withdrew into the inner apartments.
english translation