In my family Louis (or Lewis) was originally Elias or Lazarus, though I do have some Leib or Leybka too.

Similarly, in my family Celia/Cecilia, or its nickname Cissie, was originally Cyza. My great grand aunt was called Cissie Miriam Guttenberg (born Hull, England in 1870's) after her grandmother Cyza Malka Muskatenblit of Rajgrod, Lomza gubernia.

The names will vary by geographical area. Do you mean Russia itself or the Russian Pale of Settlement when the countries included Poland, Lithuania, Latvia etc.?

Jill Whitehead, Surrey, UK