Original: When AOL (Netscape's parent) drastically scaled back its involvement with Mozilla Organization, the Mozilla Foundation was launched on July 15, 2003 to ensure Mozilla could survive without Netscape.
Simplified: When America Online (AOL) (Netscape's owner) stopped its involvement with the Mozilla Organization by a lot, the Mozilla Foundation was created on July 15, 2003 to make sure Mozilla could survive without Netscape.