Guess me : Eight and five, last name and given, We are one six six six even; The first in cow, the last in..............

Question

Eight and five, last name and given,
We are one six six six even;
The first in cow, the last in oxen
Three in damsel, three in vixen.
What are we called?

Answer 1

Roman Numerals
The last name has eight letters (Numerals) while the first or given name has five (Roman).
Using each of the numerals once gives MDCLXVI, which is 1666.
C (which is found in cow) is first of the seven in the alphabet while x (which is found in oxen) is last.
Three of the seven are found in DaMseL.
Three are also found in VIXen.