The Varadaraja Perumal Temple is one of the most important temples for Sri Vaishnavas, and is also known as Perumal Kovil.
The main deity of the temple is Lord Varadaraja. The Lord is also known as Deva Perumal, Hastishan, Devadhirajan and so on. The Utsavar is known as Perarulalan (meaning, a man with great compassion). Perundevi Thayar is the name of Lord Varadaraja’s consort, and has a separate shrine in the temple. Muthuswami Dikshitar has a written the song Brihannayaki , about Perundevi Thayar. The other shrines in the temple include those of Lord Narasimha, Chakrathazhwar, Andal and so on.
The main deity of the shrine (Moolavar), along with the processional deity
The Lord is said to have come to the place, when Brahma performed a penance. He is said to have come from Uttharavedi – the Homa Kundam of Brahma’s Ashwamedha Yaga. This is said to have happened in the Satya Yuga.
The pond of the temple is known as Anantha Saras, and the Vimanam is known as Punyakoti Vimanam. Ramanujacharya accepted the holy ascetic orders from the Lord at this very pond.
A view of the Anantha Saras
The temple follows Pancharatra Agama (form of worship). The shrine is one of the 108 Divya Desams, and has been sung by Boodathazhwar, Peyazhwar and Thirumangai Azhwar. The idols of Boodathazhwar and Nammazhwar are very special in this shrine, as the hand posture is different, which is in reference to one of his Pasurams (in case of Nammazhwar).
The idol of Nammazhwar in the temple. 
The main deity of the temple was made of fig – wood (hence the shrine is also known as Athigiri). This idol was damaged due to invasions, and hence another idol was brought from Pazhaya Seevaram for worship. The wood idol is kept in a silver box in Anantha Saras, and is raised once in 40 years, and worshipped (next one being in 2019). The processional deity, due to this event, makes a trip to Pazhaya Seevaram, once a year, and blesses the devotees there.
The idol of Atthi Varadar
Ramanujacharya used to perform Jala Kainkaryam (bringing water for the worship of the Lord) at this shrine, before taking the holy ascetic orders. Vedanta Desikan has written several works in praise of the Lord, such as Nyasa Dashakam, Varadaraja Panchasat, Thiruchinnamalai. He also says that he does not want Vaikunta – Vasa, as there might not be a Lord similar over there. Interestingly, Swami Desikan is the only Acharyan, whose vigraham is taken inside the shrine of Lord Varadaraja, once a year. Swami Manavala Mamuni has also performed Mangalasasanam at this shrine, and has composed Devaraja Mangalam in praise of the Lord.
Swami Desikan performing Mangalashasanam at the shrine of Lord Varadaraja
The main temple events include the Garudotsavam, Bhogi Kalyanotsavam, Thotti Thirumanjanam and so on. Garudotsavam happens four times in a year, and is a sight one shouldn’t miss. Once, Doddacharya, who was residing at Sholingur could not make it to the Kancheepuram Garudotsavam on one occasion. He expressed his inability to the Lord, while standing on the banks of the Brahma Theertham (holy water sources also known as Thakkan Kulam). The Lord, in all His enchanting beauty, sitting on Garuda appeared before the Doddacharya, and blessed him. It is also said that during British rule, Robert Clive, the British general visited the Garudotsavam and presented a valuable necklace (now termed Clive Maharkandi), which is adorned during a special occasion every year.
Kanchi Garudotsavam, photo courtesy Sri VN Kesavabashyam
The shrine of Lord Varadaraja is atop a small hill known as Hastigiri(Attigiri). One needs to climb 24 steps to reach the main shrine. It is atop the hill, in a place called Kachiku Vaithan Mandapam, the Lord used to talk with Kanchi Purna It is also the place where Nadadoor Ammal blessed Vedanta Desikan as a kid, and used to perform Kalakshepam. Through Kanchi Purna, Ramanujacharya got His doubts from the Lord Himself, which are now known as Aaru Varthaigal. There are two lizards (Golden and Silver) in the temple, and are a tourist attraction in the temple.
The Golden and Silver Lizards found atop the hill.
The Lord is known for granting wishes (and hence the name). More so, He is known as the Lord who cures problems related to the eyes (Vedanta Desikan refers to him as Kachidanil Kannu Kudukkum Perumal). kOOrathAzhwAncomposed Varadaraja Stavam in praise of the Lord, and got eyesight to view the Lord and Ramanujacharya only. Yamunacharya performed Saranagati at this shrine, and requested the Lord to protect Ramanujacharya.
The idol of Koorathazhwan in the temple.