So many scholars, from all sides of the spectrum have many theories on why there may be previous structure at the present Tirupati temple. Let us see ourselves the evidences.
We are not going to any religious discussion or philosophical discussion, we will stick to the main point, was there a Buddhist shrine at the site of Venkateshwara temple at Tirupati.
Indology scholar Romila Thapar told -Dig underneath every Hindu temple, there will be a Buddhist temple. If we take example of Adil shah of Bhamani Dynasty, his court poet farishta tells the king demolished more than 300 major temples in karnataka and built mosques there, even in this case we cannot apply Romila Tapar and say dig underneath every mosque that adil shah built, you will find a temple, because many mosque are there which were not built demolishing a temple. The Romilla Tapar comment is pure Indologist leftist leaning. Here she is not providing any proof's, but plain rhetoric.
karthikeya( Murugan) temple.
One more claim put forth by Dravidian scholars of tamil nadu. Originally it was a Karthikeya temple and was converted to a vishnu temple. Bala means young unmarried same as Kumar(sanskrit) and Kumaran(Tamil) , which denotes to karthikeya ,but in tamil version eventhough he is called kumaran, murugan is married to Devyani(deva army) and valli ( tribal girl). So this argument is defeated there , that the murugan can be called balaji. More than that In South he is called Venkateshwara (Lord of Venkata) and only in north India he is called Balaji and in recent times.
1) First they have to prove that there was a Murugan worship was prevalent in the first millienia in tamil nadu and temples are built for murugan, For this we dont have a answer.
2) Second Pallava were ruling in Kanchi upto 9th century AD and tamil kings areas were below the pallava region.
3) Third Tirupathi came under Banas and Nolambas for most part in the first milliena. Both being Kannada Dynasties. So we dont see any murugan temple being built. Since the Kannada/ Tulu version of Karthikeya is Shanmuga. If it was a karthikeya temple, then the kannada kings might have called it shanmuga temple.
4) Fourth and most important Tamil literature right from Sangam works have always claimed that Tirupathi (Thiruvengadam) lies north of Tamil Nadu boundary.
So Tamil Scholars dont see much credit in Dravidian scholars argument that Tirupati is a Karthikeya or Murugan temple. Indology and Dravidian scholars who have worked tirelessly to undermine authentic Indian history seems have shot themselves in their foot here.
First temples in south India were built in 4th century AD in Karnataka and Andhra. Even in 6th century AD, most of the temples built were Rock cut temples, not standalone temples that we have today. All the early temples like Mamallapuram of Pallavas are also rock cut temples. So a hill temple Hindu or Buddhist standalone in Thirupathi is unthinkable.
When was Tirupati temple built?.
The Purana Accounts are legendary and is not helpful in finding the probable date of the temple. Puranas concentrate how Vishnu came voluntarily to take his place there. Varaha temple at the foothills of Tirupati predates venkateshwara temple at the top. The only account relevant here is Tondaman (pallava) started the worship of vishnu here. This Thondaman assisted his brother(Akasa Raja) in administration. Thondaiman had a foster daughter in Tirupati and she was married to venkatesa. After the death of Akasa Raja (left a young prince), he and his nephew fought and tondiaman felt very weak ,so got the weapons from venkateswara . The war ended Indecisively and the country was divided into two. The one closer to Vengadam (Tirupati) was given to thondaman and the other farther away given to his nephew. Tondaiman built the temple and started the festivals. This Tondaman lived in Kaliyuga. There is a separate Thondaiman dynasty post 12th century AD. But Dravidian scholars want to identify Thondaiman as Pallava.
We don't comes across any mention of temple in the vengadam (Tirupati) hills. Tirupati was on northside of the boundary of Tamil speaking region. Beyond this region vadukar lived with Thirayan as the chief and people spoke a language not understandable to Tamils. So no help in determining when the temple was built.
Alwar (Bakti tradition)
One Alwar called poigai Alwar gives around 12 references to temple at Tirupati and Vishnu as presiding deity. Poigai Alwar wrote Naalayira Divyap Prabhandham on the vishnava places. In some places he refers to Ilam kumara koman (May Indicate Subramanya, but the reference here is young fellow). Alwar Bhutan refers to Tirupati and Presiding deity in around 8 references in his works. Pey Alwar also refers to Tirupati. These three alwars considered worshipping vishnu with Vedic rituals as the supreme form of worshp. Some refer to the deity as ardhanari, which refers to shiva. We have to come to the conclusion here, eventhough the deity is referred as ardhanari, it may not be peculiar to shiva alone at those times. And the same goes for Ilam kumaran , may not be peculiar to subhramanya. Even though we come across stray references , we are given solid references to prove the diety is vishnu, so we should not vacillate in our judgement that the deity is not vishnu. Ardhanari shows that the temple is equally important for Lakshmi. So all the early Alwars refer to Tirupati and Vishnu deity. Tirumalisai (Bhakti sara - Sanskrit) contemproary of these three alwars wrote that he has seen all faiths and only found vishnu as great. Now we have to date the Alwars ,which is again controversial. That requires a whole article. But let us try. There is a reference to vairamegha in the early alwars work, that seemed to be identified as Rastrakuta Dantidurga, contemproary of Nandivarma pallava. But the identification needs to be proved. Commentator of Alangara kranta named Yapparungulam belonging to 11th to 12th century AD claims he is desciple of Poigaiyar (poigai alwar)and quotes two stanzas from the authors work. Tirumalisai is dated to 11th century AD. But one thing we can say is all the Alwars were born after the temple were built which was already famous.
Silapadigaram a buddhist work tells that Tirupati is Vishnu temple. In this story a Brahman of Mangadu in Malainadu goes to Tirupati and Srirangam and sings in praise of Vishnu.The Tirupati is said to be so famous that people from west coast also went to the temple. So this Buddhist epic tells very clearly that presiding diety of Tirupati is Vishnu. Dating of cilapathikaram is controversial, we have already seen in a separate article.
So let us find who this thondaman is?
We find from Sangam literature sources that Vengadam changed hands from kalvar chieftain pulli to Tondaman before the time of pandyan king who won a great victory in Talaiyalanganam. The King who won in Talaiyalanganam is mentioned in Sinnamanur plates dated to 11th century AD and kings mentioned just before this date. The same source says Tondaman ruling from pavattirai (Nellore Dist, AP). We have one more Thondaman Ilam Thirayan ruling in Kanchi. Now the Foster Daughter born to the Tondaman is not legitimate and he is said to have found her on the hills and later finds out that she is his daughter. This has been equated with Naga princess story of karikala. But Karikala meets Naga princess in outskirts of Kaveripattanam, not in Tirupati hills. So we cannot identify Tondaman with karikalan. But there is a pallava story of Pallava marrying naga princess in an inscription in kanchi as well. Perumban Arupadai which gives specific details about Kanchi Vishnu temple of Thondaman Ilam Thiraiyan is silent on Tirupati or association of thiraiyan with Tirupati, so we cannot link these two stories. Thiraiyan had a brother and nephew. He fought with the Nephew and uncle for the throne. Alwars talking about war between southern king (pandya) and Northern ruler (pallava).
The Tirumangai Alwar says that the Thiraiyan kanchi was occupied by one vairamegan. The vairamegan is suposed to be Rastrakutas. Two Rastrakutas occupied the capital one is Dandidurga and other Govinda II. This story of fight between brother and Nephew looks similar to Kampavarman pallava(relative of Western Gangas) and his kid brother Nrptunga Pallava(relative of Pandyas and also Rastrakutas). This story can reveal the struggle between the last war of succession in Pallava Dynasty before Aditya Karikalan unsurpassed the throne.
Uttaramallur by Nandivarman pallava II is the first inscription to refer to vengadam, there is no temple here still. The hill is just mentioned as Vengada ,not Thiruvengada (Sri Vengada).
In 8th and 9th centuries AD, Many Visnu temples near Tirupati received Grants from many kings, but none was given to Tirupati temple. But the same can be said about Buddhist or Murugan or Jain Temple , Kings at that time were secular, so there should be a grants even if it is any of the other holy places.
In TTD gives eleven inscription of pallavas. Earliest belong to Dandivikramadeva , which may correspond to period 833-34AD.
Even through many scholars claim many dates for Tirupathi temple construction, First Inscription in Tirupati temple is by Dandivarman pallava (830AD). So the Temple has to be built during that time.
Point is the debate about Tirupati is not just today ,but it is there right from 11th century AD. Ramanuja made arguments to kings to establish the primacy of Vishnu in Tirupati. For this we have to establish the date of Ramanuja.
Date of Ramanuja
There was a Vaishnavite Devotee called as Nadamuni. He belongs to Mannarkovil in south Arcot district. He spent most of the time in the village and sometimes in Kurukaikkavalappan Kovil, a nearby village, which was just mile after the chola capital Gangaikonda Cholapuram (Named so,After Western Ganga Territories were absorbed into chola empire in 1022AD). when he was in Kurukaikkavalappan Kovil village, he heard vaishnavite devotees singing a song in praise of Vishnu, which was Tiruvoimoli of Nammalvar. He asked the pilgrim to repeat the verses. But the pilgrim knew only ten lines of the 1000 lines poem. So he went in search of the work. He reached Kumbakonam, he got nothing. So he went to Tirunagari in Tirunelveli the native place of Nammalvar. His attempts were futile there also. So he sat under the tree of temple ,where Nammalvar is supposed to have practiced Yoga. He chanced on someone who was direct disciple of Nammalvar and got the full work. He brought the work to srirangam and revived the festival started by Thirmangai Alvar. Having done this, he went on pilgrimage to all the vaishnava shrines in the country. He went to Abhobilam and Tirupati. He went back to Tirupati as he welt the pooja arrangements were not proper. His grandson Alavandar Yamunait- turaivar or Yamunacharya. For the arrangements to become proper, he asked one of his disciples to volunteer to stay in the hill and conduct the worship in proper way. One of his grandsons Thirumalai Nambi volunteered to do the service. Thirumali Nambi settled down there and planted a garden and took upon himself to deliver water for the diety daily from a waterfall little distant from the temple. One of the young sisters that Thirumalai nambi took with him was married to one Kesava Somayaji of Sriperumbudur. The offspring of this marriage was Ramanuja. Ramanuja's date of birth, according to the traditional account of his life,is Kali 4118, A. D. 1017. The other date given of course is Saka 937 bya chronogram. Going by the story we have here ,the date has to be at the fag end of 11th century AD. The same sources give date of Nadamuni to 3684, which would mean A. D. 582-83. So these date cannot be trusted. Ramanuja visted the tirupati temple once in his childhood. The temple after Thirumalai Nambi was managed well except during one time of Gopinath. The local ruler Yadavaraja found some dispute between Shaivas and Vaishnavas regarding the temple and called in court the warring parties to settle the matter. Ramanuja explained clearly that the temple is vaishnavite and the matter was settled that the temple was Vaishnavite. And the Vaishnavites were given more unoccupied land in the base of the hill for settlement. So through the discussion we have seen that the Ramanuja is in 11th and possibly extended to 12 century. So the earliest dispute seems to be between Shaivites and vaishnavites, which has been decided in favour of Thirupati being Vishnu temple.
The Conclusion is that the Tirupati is a Vishnu temple all along. Since the temple has been built in 9th century AD. It is after 9th century AD that the hill is said to be holy place. So any account which says that the hill is holy(sri or Thiru venkata) is after 9th century AD. This applies any work or devote singing on Tirupati. The dispute seems to be primarily between Shivite and Vaishnavite, because of the Shiva Temple at the base of Tirupati which predate the Tirupati temple. Indologist seems to have introduced some confusion here. There are no inscriptions about Tripati temple, before 9th century AD, because the temple did not exist then, not because it was a Buddhist Shrine.
Tirupati Balaji was a Buddhist Shrine
by K. Jamanadas
History of Holy Shrine of Sri venkatesa in Tirupati by Krishnaswamy Aiyangar