This fourth part of the 'Materialien zur Geschichte der Ramanuja-Schule' is an attempt to trace in philological and historical terms the theologoumenon's development of the doctrine of the 'Inner Ruler' following the texts handed down to us and to prevent an expose of its theological substance. The doctrine is followed up in the work of Sankara (ca. 800 A.D.), in the Subalopanisad, in Bhaskara's Bhedabhedavada (about 900 A.D.) up to the adoption of Antaryami in the Brahma-doctrine of Ramanuja. Finally, after the exposition of the influence of tantric thought, the doctrine of Antaryami is treated with regard to the late period of the Ramanuja-school. This investigation is of importance not only because of the collection of the relevant texts regarding this doctrine, but also in view of the necessity of examining the emergence and development of this school not only from the standpoint of the Vedantic Brahmadoctrine, but to evaluate this school as what it has become in the sense of 'Sitz im Leben', i.e. one of the significant 'religious traditions' of Vaisnavism, whose Brahma-doctrine has developped into a fully-fledged theological world view.