Evolution of Surnames

Hi,
I was very much interested in the discussion in Spanish of the evolution of
surnames. I can kind of translate it as I read it, but there are some parts
that I am not getting. This is a very interesting topic. Can anyone give a
brief translation of this discussion? I get the part about their being
separate books for baptisms of hijos naturales and for the indios, because I
have seen this for myself. What I am not quite understanding, is the part
about the "siglo," where I think it is saying that the indigenous population
had to pay some sort of tribute? Well, can someone explain that part, which
must be referring to the early part of Mexico's Spanish history within New
Spain, I am guessing.

Thanks,
Corrine Ardoin
Santa Maria, California