MySQL was founded by Monty Widenius, David Axmark and Allan Larsson in Sweden in 1995, and rapidly became an essential element of the LAMP (Linux/Apache/MySQL/ Perl) stack which enabled the breakthrough of free and open source software in the Nineties.
MySQL was light and fast, and a popular choice for use in web applications. It was also free, and pioneered the use of dual- licensing – or the practice of releasing the code simultaneously under free or proprietary licences.
Dual licensing has always been controversial because it relies on copyright assignment and the willingness of third-party developers to surrender ownership of the code to a controlling company or organisation. Its virtue is the perception that it encourages companies to release code under a free software licence.