The New Stack takes us on a fun trip down memory lane:

Fifteen years ago a number of the Linux kernel developers tossed their hands in the air and gave up on their version control system, BitKeeper. Why? The man who held the copyright for BitKeeper, Larry McVoy, withdrew free use of his product on claims that one of the kernel devs had reverse engineered one of the BitKeeper protocols.

Linux creator Linus Torvalds sought out a replacement to house the Linux kernel code. After careful consideration, Torvalds realized none of the available options were efficient enough to meet his needs: