Back in April of 1976, Xerox PARC developed the first portable prototype, called the Xerox NoteTaker, but it never hit the market. The first portable laptop hit the market in 1981, it was called Osborne 1. It sold for $1795 and had a whopping 5-inch display and weighed 24.5 pounds.
Just imagine carry that thing around! You can find more information here: laptopsarena.com/who-invented-the-laptop.