It's the company that now owns Diners Club (and is better known under that name in many countries other than the US), who in turn invented credit cards way back :)
They did start the first payment card that wasn’t linked to a specific company (i.e. the American Airlines card).
Store accounts/cards have indeed been around significantly longer.
The distinction between a credit and a charge card is not that relevant in that context, in my view: For both, you spend an issuer’s money at unaffiliated merchants and pay the issuer back later.