In Europe and Australia, the system was released to two separate marketing regions. One region consisted of most of mainland Europe (excluding Italy), and distribution there was handled by a number of different companies, with <answer>Nintendo</answer> responsible for most cartridge releases. Most of this region saw a 1986 release. Mattel handled distribution for the other region, consisting of the United Kingdom, Ireland, Canada, Italy, Australia and New Zealand, starting the following year. Not until the 1990s did <answer>Nintendo</answer>'s newly created European branch direct distribution throughout Europe.
Who released cartridges in mainland Europe?
Nintendo