Continental fragmentation is one of the most fundimental processes that shape the face of our planet. The forces that cause plate tectonics can break continents apart, with rifts systems that occasionally propogate through very old and cold continental plates. Nonetheless, classical models fail to predict breakup of old continents. We have developed a new dynamic theory, where the heat generated by deformation can significantly reduce the strength of plates. We propose to apply this theory to the dynamic strength of continents, adding potential weakening through magmatism and systematically analyse rift systems. This will overhaul the way we model continental deformation.