Abstract: Minimal string theories provide some of the simplest examples of holographic dualities, where low-dimensional theories of quantum gravity are dual to matrix integrals. The most studied example is the worldsheet theory defined by the A-series minimal model coupled to Liouville CFT, which is dual to a solvable two-matrix integral. In this talk I will give an overview of low dimensional string theories and discuss new aspects of the D-series minimal model coupled to Liouville, which is conjectured to be dual to an unsolvable four-matrix integral when the minimal model is unitary. Based on work in progress with Victor Rodriguez and Zi-Yue Wang