Conversation so far:
What are the main roles?
Out of about 750 hereditary peers, only 92 may sit in the House of Lords.
Who are the House of Lords?
CANNOTANSWER.
Are there any other interesting aspects about this article?
Until 1963 peers could not disclaim their peerage in order to sit in the House of Commons.
Why is that?
CANNOTANSWER.

Question: What roles do they have in the peerage system?
Self-contained rewrite: What roles do the peers have in the peerage system?