One of the major unresolved issues of Seljuq history is the balance of power between the Sultans and their great magnates in the period between the death of Malik-Shah in 1092 and the practical downfall of the Great Sultanate with the death of Sanjar in 1157. The issue of the fractious tendencies of the magnates and the extent to which they undermined Seljuq political stability is particularly fraught in relation to the Seljuq downfall, for which the alleged feudalism of the over-mighty amirs has been blamed. Yet very little research has actually examined the post-Malikshah period of Seljuq rule; and nearly all of that research has focused exclusively on the years of the succession struggle to Malikshah, which lasted from 1092 until 1105. Thus, many of the generalized conclusions about the state of the entire late Seljuq polity until the end of the Great Sultanate in 1157 are based on observations of the anomalous succession crisis years, or of relatively weak subordinate sultanates rather than the direct rule of the Great Sultan. As a result, the prevailing opinion among scholars is that the power of the Great Sultans was permanently and fatally weakened during the succession struggle to Malikshah, from which the Seljuqs never recovered. This paper will argue, contrary to currently accepted theory, that the Seljuq Great Sultans Muhammad (1105-1117) and, to a much greater degree, Sanjar (1117-1157), restored the power and authority of the Seljuq sultans, and succeeded in reversing the centrifugal or "feudal" tendencies which had taken root during the succession dispute. It will be shown that Sanjar was well able to hold his amirs in check until his grip over his magnates was weakened by old age. In order to prove this thesis evidence will be adduced from both literary and non-literary sources. The Persian and Arabic literary sources utilized will include dynastic histories such as al-Husayni's Ta'rikh al-Dawla al-Saljuqiyya, al-Bundari's Zubdat al-nusra, Ravandi's Rahat al-Sudur, and Zahir al-Din Nishapuri's Saljuqnama; general histories such as the works of Ibn al-Athir, Ibn al-Jawzi, Sibt Ibn al-Jawzi, Mirkhwand, Rashid al-Din, Qazvini, and others; local histories such as Zamchi Isfizari's Rawdat al-jannat fi awsaf madinat Harat and Bayhaqi's Tarikh-i Bayhaq. Evidence will also be adduced from the non-literary sources: namely, the abundant numismatic evidence, which has never before been exploited for this purpose, yet which is critical for the elucidation of political relations during the late Seljuq period.