The rise and fall of the 30-year friendship between Bill Gates and Warren Buffett

• Bill Gates and Warren Buffett have been friends for over 30 years.
• After hitting it off in their first meeting, they worked together on philanthropy for decades.
• But their relationship appears to have cooled in recent years.

Warren Buffett and Bill Gates, who both rank high among the richest men in the world, have been friends for decades. It began in the 1990s and led to joint ventures and world-changing philanthropy.

But in recent years, both their business and personal relationships have cooled.

Here's what happened.