Emrys is the Welsh form of the Latin Ambrosius, meaning immortal or enduring, a name tied in legend to a prophetic figure who influenced the Arthurian tradition. It suggests permanence -- something that outlasts its immediate moment rather than fading with circumstance.
The virtues of the planets are received by the Sun, when he is posited either in the ascendant or midheaven, in conjunction of them. The Moon in the night-time receives them also, if in the aforesaid places, she be joined to them. - William Lilly (1602.-1681.)