The Cheras occupied the country northward of the kingdom of Pandya, and westward of Chola, including a considerable part of what is now known as Mysore. Their rise according to their own annals took place nearly at the time of the Christian Era, but this most probably is an exaggeration; but there are inscriptions which prove that they were powerful in the 4th and 5th centuries. From this time they seem gradually to have extended their conquest northwards. Their sixteenth king boasts of having conquered Andhra and Kalinga,[352] and their twentieth king, Kongani Raya III., boasts of having conquered Chola, Pandya, Dravida, Andhra, Kalinga, Varada, and Maharastra desas as far as the Nerbudda river.[353] According to the dates in the Kongadesa Rajakal, this must have taken place in the 7th century, but from what we know of history, it could not have taken place till after the overthrow of the Chalukyan dynasty, and consequently hardly before 750. That a southern conquest did take place about that time seems almost certain from the eclipse of the Chalukyas between 750 and 1000,[354] and from the excavation of the Kylas and other temples of Dravidian architecture at Ellora about that time, and there seems no race but the Cheras who could have effected this. Vira Chola (A.D. 927-977) seems first to have checked their victorious career, and Ari Vara Deva, another Chola king (1004), to have completed their destruction. He also boasts of having carried his victorious standard to the Nerbudda, and to have been a benefactor to Chillambaram, the then famed temple of his race. This was the last great effort of the early triarchy; after this the rise of the Bellalas in Mysore, and the revival of the Chalukyas in central India, seem to have checked them to such an extent, that they never regained a perfect independence, though at times wealthy and powerful and capable of embarking in the most splendid architectural undertakings.[355] Although, politically, these three states always remained distinct, and generally antagonistic, the people belonged to the same race. Their architecture is different from any other found in India, but united in itself, and has gone through a process of gradual change from the earliest times at which we become acquainted with it, until we lose sight of it altogether in the last century. This change is invariably for the worse, the earlier specimens being in all instances the most perfect, and the degree of degradation forming, as mentioned above, a tolerably exact chronometric scale, by which we may measure the age of the buildings.