The kingdom or empire of Vijayanagara takes its name, 'City of Victory', from its capital on the Tungabhadra River, near the centre of the sub-continent. Among Indian kingdoms, a rule of three centuries is very long and this together with the large territory over which Vijayanagara kings reigned makes it one of the great states in Indian history. Vijayanagara historiography also changed because of Krishnaswami Aiyangar's insistence that literary evidence of that period should have as much standing in the interpretations of historians as epigraphy and archaeology. Nilakanta Sastri's major contributions to Vijayanagara history were of another sort. Nilakanta Sastri's efforts in the 1950s to make Vijayanagara out to be a centralised empire has influenced subsequent writing on in two ways, both negative. Nilakanta Sastri made the centre of his interpretive analysis the onslaught of Islam. The military consequences of this led to what he called the 'war state' of Vijayanagara.