The demon Sallos appears in the grimoires The Discoverie of Witchcraft, The Book of the Office of Spirits, Pseudomonarchia Daemonum, and The Lesser Key of Solomon
From The Lesser Key of Solomon, Crowley/Mathers edition:
The Nineteenth Spirit is Sallos (or Saleos). He is a Great and Mighty Duke, and appeareth in the form of a gallant Soldier riding on a Crocodile, with a Ducal Crown on his head, but peaceably. He causeth the Love of Women to Men, and of Men to Women; and governeth 30 Legions of Spirits. His seal is this, etc.
Timeline of related events
1536Publication of De praestigiis daemonum (lists this demon)
1563First known appearance of The Book of the Office of Spirits (lists this demon)
1584Publication of The Discoverie of Witchcraft (lists this demon)
1641Publication of the Lesser Key of Solomon (lists this demon)