what is known as the tripartite …

The Tripartite Struggle for control of northern India took place in the ninth century. The struggle was between the Pratihara Empire, the Pala Empire and the Rashtrakuta Empire.[1]:20
Towards the end of the successor of Nagabhata II,the ruler of pratiharas successfully attacked Kanauj and established control there. This was short-lived as he was soon after defeated by the Rastrakuta ruler, Govinda III. However the Rastrakutas also formed a matrimonial relationship with the Gangas and defeated the kingdom of Vengi. By the end of the 9th Century the power of the Rastrakutas started to decline along with the Palas. This was seen as an ideal opportunity by the feudal king Taila II who defeated the Rastrakuta ruler and declared his kingdom there. This came to be known the Later Chalukya dynasty. Their kingdom included the states of Karnataka, Konkan and northern Godavari. By the end of the tripartite struggle, the Pratiharas emerged victorious and established themselves as the rulers of central India.