Conversation so far:
When was Cardiff RFC's rebel season?
Cardiff RFC rebel season occurred during the 1998–99 season.
Why was the Welsh Rugby championship replaced?
In 1990, the unofficial Welsh championship was replaced by a league structure involving promotion and relegation.
What was Cardiff RFC's record during the rebel season?

Question: Did they win the championship?
Self-contained rewrite: Did Cardiff RFC win the championship during the rebel season?