The kUrma purANa mentions an ancient temple of nR^isiMha in mUlasthAna. The city seems to have been a major center for the worship of mitra and sUrya in the Iranian tradition. Below is the paurANic tale from the bhavishyata (chapter 139), recollecting the same :
kR^ishNa vAsudeva, the hero of the yadus, married jAMbavati, the daughter of the bear-king jAmbavAn. Their son was the valiant sAmba. He crossed the salty sea from dwAravati and went to the banks of the river chandrabhAga. Here, he founded the city of mUlasthAna constructed temple in the honor of sUrya. No local brAhmaNa knew of the mysteries of his worship and hence could not take up priesthood at the temple. So sAmba sought
help of gauramukha, the adviser of the yadu chief, ugrasena. gauramukha asked him to go to shakadvipa and obtain a special class of priests called magAchAryas to worship sUrya. saMba said: ” pray, tell me Oh brAhmaNa what are the antecedents of these worshippers of the sun. ” gauramukha narrated: “The first of the brahmins amidst the shakhas was called sujihva. He founded a gotra termed the mihira gotra. He had a daughter of the name nikShubhA. sUrya was enamoured by her and impregnated her. Thus she gave birth to jarashabda who was the founding father of all the magachAryas. They are distinguished by the sacred thread called the avyanga that they wear around their waist”.
saMba there upon called on kR^ishNa to send him garuDa and flying on his back he landed in shaka dvIpa. He collected the magAchAryas, brought them back to bhArata and installed them as priests of his sUrya temple.
The Idol of sUrya should be constructed thusly:
He should have a human form with a solar corona placed behind him. He should be on a chariot with the horses standing for the seven solar rays. He should hold a chakra and trishula in two arms, and lotuses in the other two. His feet should be covered by boots upto the knees. His waist should bear the avyanga.
This temple in mUlasthAna was situated in what is now the terrorist state of Pakistan. It was ravaged by early Mohammedan invaders, including the Karmathians, (refered to by Al beruni too) and finally completely demolished by Awrangzeb.
The magAcharyas were the Indian remnants of the shakas. From the pauraNic tale one may infer that they were concentrated around mUlasthAna and were absorbed into the older lore about the city involving sAmba.
The main lineages of the Sakas were: The Saka Tyaiya Paradraya (the far away Sakas, also called Scythians) whose kingdom lay to the north of the Black Sea and stretched out into the steppes of Ukraine. The Saka Tigra Khauda (the pointed capped Sakas) occupied the territory to the north of the Aral and Caspian Seas. The Saka Haumavarga (the soma pressing Sakas) occupied the Central Asian Steppes south east of the Aral and North West of bAhlika (Balkh) and mUjavAnt. To their East there was also a Saka lineage in Khotan and Tumushq. Additionally the North Iranian group included the Sairima (Sarmatians) who were between the Saka Tyaiya Paradraya and the Saka Tigra Khauda. Elements of the Alyani (Alans) speaking a North Iranian tongue existed in the Caucasus.
The Sakas of Western India were the Saka Haumavarga. In many ways their priesthood was recognizably similar to the brahmins allowing assimilation in India. These Sakas migrated into India after they met with a disastrous defeat in central Asia, where their King spalagadama was killed by the Huns under Motun-Tegin. Their priesthood also appear to have coopted the Zarathushtran cult after a struggle during the Achaemenid period giving rise to the Magas of Iran. They restored the polytheistic spirit of the old Aryans by incorporating their hymns, the yashts into the Avesta.
Note that the Indian sanskritize zarathuShTra as jaraShabda rather than the etymologically harituShTra, suggesting that this tale was coined well after Zarathushtra’s time.