Most weapons since the Middle Ages can be identified as having been developed by a particular country. This may be as a result of that nation's government or military driving development, or in some cases of private citizens or companies creating new technologies. In most cases, if successful, the invention will spread to other nations. In general, weapons should be listed under the nation which led the development of the project, even if use and production may have spread. In cases where development was the result of shared collaboration between partner nations, the weapon should be found in Category:International weapons