NPR:
In 1983, Mockapetris developed a protocol that associated strings of numbers with an easy-to-remember name. For instance, the IP address 216.35.221.77 is npr.org. You can type either one into your Internet browser and get NPR’s Web site, but it’s much easier to remember npr.org.
Mockapetris’ system is referred to as the DN — the domain name system —and it’s one of the fundamental building blocks of the Internet.
[…]
“I tend to think of that as sort of the dinosaur age,” Mockapetris says. “1983 was the year we had a big change-over to IP, TCP, DNS and all of these new protocols. It was sort of the start of mammals on the Internet.”
Computers were suddenly able to talk with computers on different networks, creating an interconnected network — or the Internet, as we know it today. Mockapetris realized early on that to accommodate all the millions or more addresses that were about to bloom, they were going to need a better naming system.
You can read more about DNS here.