Saravali

Kalyana Varma, the famous author Saravali belonged to the 10th century AD. He was the king of a place called Vyaghrapada, believed to be somewhere in Madhya Pradesh. From the verses in this work it is obvious that he has studied the works of Parashara, Varahamihira and Yavana etc before him, and as he felt that they were too brief, he decided to elaborate the principles.
Saravali indeed is a monumental work and the study of it is a must for the serious students of astrology.