The first web browser was invented in 1990 by Sir Tim Berners-Lee. It was called WorldWideWeb (no spaces) and was later renamed Nexus.
In 1993, browser software was further innovated by Marc Andreessen with the release of Mosaic (later Netscape), "the world's first popular browser", which made the World Wide Web system easy to use and more accessible to the average person. Andreesen's browser sparked the internet boom of the 1990s. The introduction of Mosaic in 1993 – one of the first graphical web browsers – led to an explosion in web use. Andreessen, the leader of the Mosaic team at NCSA, soon started his own company, named Netscape, and released the Mosaic-influenced Netscape Navigator in 1994, which quickly became the world's most popular browser, accounting for 90% of all web use at its peak (see usage share of web browsers).