[soltakss]

BRP and RQ derive from the same, or similar, rules-sets.

I am probably wrong here, but this is how I understand it:

BRP derives from Call of Cthulhu and Stormbringer 5 with some RQ3 thrown in. The base Call of Cthulhu are derived from BRP which was a cut-down version of the RQ Rules. The original Stormbringer was based on a similar set of rules to RQ2, but was quite a bit different, it evolved through various Stormbringer and Elric games until Stormbringer 5 which a lot of people consider to be better than RQ3, if such a thing were possible.

Mongoose RuneQuest derives somewhat from RQ2 and RQ3 but is heavily different. RQ3 derived from RQ2. RQ1 did exist but is almost the same as RQ2, RQ1 was written for Chaosium and wasn't based on anything else.

So, from a system point of view they are similar.

However, Chaosium lost the rights to RQ when they sold it to Avalon Hill. They got the rights to the RQ system, but not Glorantha, when Avalon Hill stopped publishing for a number of years (as I understand it) but Greg Stafford's Issaries gained the RQ Trademark and commissioned a new version of RuneQuest. Chaosium brought out BRP which is based on their own rules system.

So, they are owned by two different and rival companies and are no longer connected, despite a shared past.

BRP is not RuneQuest and RuneQuest is not BRP. But both are d100.

I hope that doesn't help.