Prince2 is a structured, non-proprietary project management method focusing on controlling project costs, timescales, quality, scope, risk and benefits. The purpose of PRINCE2 is to provide a project management method that can be applied regardless of project scale, type, organisation, geography or culture. This is possible because of the fact that PRINCE2 is principles-based.
They provide a framework of good practice for the people that are involved in a project. The PRINCE2 Principles are the basis of what defines a PRINCE2 project: if you say that you are working on a PRINCE2 project, all seven principles must be applied in that project.