I am just quoting the para about Sanyo, Prithvi and Sanyo's brother whose name was Harichandra.Those who want to read the whole history, the site link is below😊
During 1089-90 A.D. Chandradeva the first Gahadavala king of Kannauj ruled and have protected the sacred places of Kushika (Kannauj). Kannauj once more recovered a large measure of its old importance during 1114 A.D. to 1154 . During the reign of Chauhans (1170-1194 A.D.) Kannauj became powerful and annexed to Delhi. Kannauj (Jaichandra's capital) was the scene of Svayamvara of his daughter Samyogita, who was carried off by Prithviraj III. Mohammad Ghauri invaded India and killed Jaichandra in 1193 A.D.
Jaichand's son, Harichandra continued to occupy Kannauj even after 1193 A.D. The Muslim supremacy over the kingdom was perplexing or abhorrent to him and so he discreetly omitted any specific reference to Harichandra or his Muslims overlord. In 1233-34 Iltutmish ordered the Kannauj Garrison to join the imperial forces in an expedition against Kalinjar. In 1244, The district of Kannauj was conferred by the dissolute Alauddin Masaud on his uncle Jalaluddin for his maintenance. The royal forces reached Kannauj and besieged the fort of Balsandah. This fortress was very strong and the royal forces returned with immense booty.
I got the info from http://kannauj.nic.in/history.htm (Kannauj's official site)