Let's travel back in time, to the Bitcoin v0.1 Alpha era, to be exact.
"You can get coins by getting someone to send you some, or turn on Options->Generate Coins to run a node and generate blocks. I made the proof-of-work difficulty ridiculously easy to start with, so for a little while in the beginning a typical PC will be able to generate coins in just a few hours. It'll get a lot harder when competition makes the automatic adjustment drive up the difficulty. Generated coins must wait 120 blocks to mature before they can be spent."
https://web.archive.org/web/20090131115053/http://bitcoin.org/