Sadasiva Brahmendra was a saint, a composer of Carnatic music and an Advaita philosopher who lived near Kumbakonam, Tamil Nadu during the 18th century. He composed mainly in Sanskrit. Only a few of his compositions have survived but they are recognised as great compositions of Carnatic Music.
Sadasiva was born to a Telugu couple Moksha Somasundara Avadhaani and Parvati. His initial name was Sivaramakrishna. He was married at the age of 17. Sadasiva lived in Kumbakonam, near Tamil Nadu in the 17th to 18th century. Two other prominent Hindu saints Sridhara Venkatesa Ayyaval and Sri Bodhendra Saraswathi were his classmates in the veda school.
He left his home in search of Truth and went to Kanchipuram. He was divinely guided to go to the Upanishad bramham Mutt at Kanchipuram to Sri Paramasiva Brahmendra Saraswathi, who was presiding over the Mutt at that time. Later, after taking sannyasa, he is said to have wandered around, naked or semi-naked, and often in a trance-like state. He was reclusive and often meditated, and was described as being in a "supremely intoxicated state". He is said to have performed many miracles whilst alive, some of the most prominent are provided below. His jiva samadhi site is briefly mentioned in 'Autobiography of a Yogi' by Paramahamsa Yogananda.
On the river banks of Cauvery in Mahadhanapuram, he was asked by some children to be taken to Madurai, more than 100 miles away, for an annual festival. The saint asked them to close their eyes, and a few seconds later they reopened their eyes and found they were in Madurai. He also wrote the Atma Vidya Vilasa, an advaitic work.
There is an epilogue to this story. The next day, another youth, incredulous at hearing this story, asked Sadasiva to take him also to this festival. It is said that the youth immediately found himself in the distant city. When it was time to return, Sadasiva was nowhere to be found. The youth had to make his way back on foot.
Whilst relaxing near a heap of grains, he began meditating. The farmer who owned the land mistook Sadasiva for a thief, and confronted him. The farmer raised his stick to hit the saint, but became a statue. He remained in this state until the morning, when Sadasiva finished meditating and smiled at the farmer. The farmer was restored to his normal state, and asked the saint for forgiveness.
At another time, while meditating on the banks of the Cauvery river, he was carried away by a sudden flood. Weeks later, when some villagers were digging near a mound of earth, their shovels struck his body. He woke up and walked away.
Long after all these happened when almost people had forgotten the memories of his wandering in their lands, once the naked sannyasi was seen walking right through a Muslim harem of a Nawab. As a brahma-jnani who sees nothing but brahman everywhere, he would not distinguish between the different human figures which cross his path nor would he be distracted by the sights or noises that his environment may present to him. It was in this state of trance that he was walking along. He, the naked sannyasi, walked straight into the harem, entering it at one end and walking out at the other all the while walking through a maze of inmates of the Nawab’s harem. The news reached the nawab, he had his men chase him, they cut off both his hands as he was walking along, the hands fell off and … still he was walking along silently as if nothing had happened. The Nawab got scared, picked up the hands that had been severed, ran to the Sage and offered them in total remorse. The sage stopped his walking, the severed hands were restored to their place, the hands became normal and the sage walked away! There was no conversation.
He is said to have met the Raja Thondaiman of Pudukottai and initiated him into the Dakshinamurthy Mantra. He is said to have written the mantra on sand. This sand was picked up by the king and it is in the worship of the royal family till now in the Dakshinamoorthy temple inside the Pudukottai palace in Pudukottai. 
He was responsible for installing the deity Punnainallur Mariamman near Thanjavur and guided the installation at Devadanapatti Kamakshi temple. He also installed the Hanuman Murthi in the Prasanna Venkateswara temple at Nalu Kal Mandapam in Thanjavur.
He also installed Lord Ganesh and a powerful Ganesh Yantra at the Thirunageshwaram Rahu Stalam temple at Kumbakonam.An inscription in the temple bears testimony to this fact. The shrine can still be seen at the entrance to the temple.
He has three samadhis :
Every year in Nerur and Manamadurai, music festivals are conducted in his honor. In Manamadurai his samadhi is located at the Somanathar temple, which was identified by the Paramacharya of Kanchi.
Sri Sri Sacchidananda Shivabhinava Nrusimha Bharati, pontiff of the Sringeri Saradha Peetham had visited Nerur and composed two slokas in praise of Sri Sadasiva Bramhendra - Sadasivendra Stava and Sadasivendra Pancharatna 
He is the author of several Sanskrit works. The following works have been printed/published.
- Brahmasutravrutti or brahma tatva prakashika
- Yoga Sudhakara which is a commentary on the Yoga Sutras of Patanjali.
- Siddhanta kalpavalli
- Atmavidhya vilasa
- Dakshinamurthy Dhyanam
- Shivayoga Dipika
The following works are ascribed to Sri Brahmendral but no printed version is available.
- Suta Samhita
- Atmanatmaviveka prakashika
He also wrote several Carnatic compositions to spread the advaita philosophy among common people. His compositions are quite popular and can be heard frequently in Carnatic music concerts. Some of these are
- Ananda Purna Bodhoham Sachchidananda - Shankarabharanam
- Ananda Purna Bodhoham Satatam - Madhyamavati
- Bhajare Gopalam - Hindolam
- Bhajare Raghuviram - Kalyani
- Bhajare Yadunatham - Peelu
- Brahmaivaham - Nadanamakriya
- Bruhi Mukundethi - Gowla, Navaroju, Kurinji, Senchurutti
- Chetah Sreeramam - Dwijavanthi, Surati
- Chinta Nasti Kila - Navroj
- Gayathi Vanamali - Gavathi, Yamuna Kalyani
- Khelathi Brahmande - Sindhubhairavi
- Khelathi Mama Hrudaye - Atana
- Kridathi Vanamali - Sindhubhairavi
- Krishna Paahi - Madhyamavati
- Manasa Sanchara Re -Sama
- Nahi Re Nahi Re - Gavathi
- Pibare Rama Rasam - Ahir Bhairav
- Poorna Bodhoham - Kalyani
- Prativaram Varam - Todi
- Sarvam Bramha Mayam - Mishra Sivaranjani
- Smaravaram - Jog
- Sthiratha Nahi Nahire - Amruthavarshini
- Tatvat Jeevitham - Keeravani
- Tunga Tarange Gange - Hamsadhwani
In the Movies
Character of Sadasiva Bramhendra is portrayed in the Tamil movie Mahashakti Mariamman
In popular Culture
Tamil writer Balakumaran has written a novel Thozhan based on the life of Sri Sadasiva Brahmendra.
- "Sadasiva Brahmendra (18th Century)". Retrieved 2 December 2010.
- "Commentaries of Sadasiva Brahmendra on Brahmasutra & Yogasutra". 29/07/2010. Retrieved 2 December 2010.
- "Sri Sadashiva Brahmendra – the Avadhuta". Retrieved 2 December 2010.
- "Sri Sadasiva Brahmendral - Part II ...Contd". 03/07/2007. Retrieved 2 December 2010.
- "Autobiography of a Yogi by Parahamsa Yogananda". Retrieved 20 June 2011.
- Devi R, Priya (03/07/2007). "Sri Sadasiva Brahmendral - Part II". Retrieved 2 December 2010.
- "Sadasiva Brahmendra: Perhaps two of the greatest mystics of India belong to the Tamil region". Retrieved 27 July 2012.
Brahmatatvaprakasika nama Brahmasutravrttih - http://www.dkagencies.com/doc/from/1023/to/1123/bkId/DK8263321716226271789703045171/details.html