The first Elvis music on CD was issued by RCA in Europe in November 1983 in the form of a 3CD box set called Elvis:The Legend. This was a 60 track compilation of his classic hits. The box was a limited edition of 5,000. The same tracks were recompiled into 4 volumes of a series called The Collection and issued early in 1984.
Read the story of how the box set was produced and released and why from Europe and not the USA here
Volume 1 - PD 89248
Volume 2 - PD 89249
Volume 3 - PD 89472
Volume 4 - PD 89473