Hoyt & Roberts, comps. Hoyts New Cyclopedia of Practical Quotations. 1922.
Janus was invoked at the commencement of most actions; even in the worship of the other gods the votary began by offering wine and incense to Janus. The first month in the year was named from him; and under the title of Matutinus he was regarded as the opener of the day. Hence he had charge of the gates of Heaven, and hence, too, all gates, Januæ, were called after him, and supposed to be under his care. Hence, perhaps, it was, that he was represented with a staff and key, and that he was named the Opener (Patulcius), and the Shutter (Clusius). M. A. DwightGrecian and Roman Mythology. Janus.