Mosaic -- The First Global Web Browser

Marc Andreessen, Helped develop Mosaic and Netscape
Marc Andreessen

NCSA Mosaic is free for internal use by commercial organizations, and is also available for licensing by commercial organizations for modification and/or distribution. For information, please contact the author. For more information on the NCSA Mosaic project in general, please feel free to contact the author.

– Marc Andreessen, NCSA Mosaic Technical Summary, Feb 20, 1993.

Marc Andreessen and his team invented Mosaic (original NCSA page), the first popular Web browser, which greatly helped spread use and knowledge of the web across the world.

In 1992, Joseph Hardin and Dave Thompson worked at the NCSA (National Center for Supercomputer Applications), a research institute at the University of Illinois. When they heard about Tim Berners-Lee’s work, they downloaded the ViolaWWW browser, and then demonstrated the web to NCSA’s Software Design Group by connecting to the web server at CERN over the Internet. The group was duly impressed.

Two students from the group, Marc Andreessen and Eric Bina, began work on a browser version for X-Windows on Unix computers, first released as version 0.5 on January 23, 1993. His release message was forwarded to the newsgroups by Berners-Lee six days later, seeding subsequent redistribution and wider awareness. Bina provided expert coding support. Andreessen provided excellent customer support, monitoring the newsgroups continuously to ensure that they knew about and could fix any bugs and make desired enhancements.

A version of Mosaic for the Macintosh was developed by Aleks Totic and released a few months later, making Mosaic the first browser with cross-platform support.

One of the NCSA’s missions is to aid scientific research by producing non-commercial software, giving Hardin and Thompson a ready-made vehicle to set up a funded project to develop Mosaic as a free, publicly available browser, managed by Hardin, and with Andreessen as the software lead.

Mosaic built on Berners-Lee’s server, and provided support for graphics, sound, and video clips, maximizing the capabilities of the DSL-based connections of the time. An early version introduced forms of support, enabling many powerful new uses and applications. Innovations with the use of bookmarks and history files were added. Mosaic quickly became the most popular web browser, helping accelerate the growth in web use and availability even more.

In August, 1994, NCSA assigned all commercial rights to Mosaic to Spyglass, Inc. Spyglass subsequently licensed their technology to several other companies, including Microsoft for use in Internet Explorer.

The NCSA stopped developing Mosaic in January 1997, since Netscape and Microsoft began to bring large development teams to bear on development of their own browsers.

Resources. The following references provide more information:

  • Andreessen, Marc; NCSA Mosaic Technical Summary; National Center for Supercomputing Applications; February 20, 1993.
    (Here under the name “”, and here under the name “” for Revision 2.1 from 8 May.)
  • A list of home pages of early Netscape programmers can be found linked on the Netscape About page.