For each of the ethical theories on this site, a biography of the key figure(s) is included. This gives useful background to the theory, and can help put it in a context, both in terms of time and influences. The Conscience is different in that it is not a theory itself, although there are many thoeries to explain the conscience.
There are some basic biographical pointers in the main text, although for Aquinas you will find this elsewhere. However, for a more thorough treatment, I would recommend wikipedia: