How did Ben Horowitz make his money?

I'm curious to know, how did Ben Horowitz accumulate his wealth? Did he found a successful startup and sell it for a massive profit? Or did he invest wisely in various companies and reap the rewards over time? Perhaps he has a unique approach to finance and investing that has allowed him to amass his fortune. I'm eager to learn more about the journey that led him to become the successful individual he is today.