What do founders actually look for when hiring their Founding Engineer?

I'm a software engineer looking to join an early-stage startup as a Founding Engineer.

For founders and early startup employees:

• What made you hire your first or second engineer?
• What skills or qualities mattered more than experience?
• Where have you found strong Founding Engineers outside your own network?

I'm particularly interested in 0→1 product development and would like to understand what founders actually look for when making these hires.

I'd appreciate hearing about your experience from either side of the table.