Yamunacharya atau Alavandar ialah seorang ahli falsafah Vishistadvaita di Sri Rangam, India. Beliau lahir pada awal kurun ke-10 Masihi dan merupakan cucu Nathamuni. Nathamuni ialah seorang yang terkenal sebagai pengumpul ayat-ayat suci Tamil Alvar.
was a vishistadvaita philosopher in Srirangam, Tamil Nadu, India. Ramanuja, one of the leaders of the srivaishnava school sought to be his disciple. He was born in early 10th century CE and was the grandson of a Brahmin, Nathamuni. Nathamuni was a famed yogi who collected to the works of Tamil alvars. He grew up learning Vedic texts from Rama Misra also known as Manakkal Nambi and was skilled in mimansa. Sirvaishnavite legend relates this history—As a teenager he challenged the royal priest Akkiyalvan of the Pandya king (the name of the king is disputed). Akkiyalvan, when he saw the age of the youth, asked sarcastically "alavandara?" meaning "has he come to rule me?". He defeated Akkiyalvan by proving through the accepted rules of logic that Akkiyalvan's mother was barren, the king was not righteous and the queen unchaste. The king and queen, impressed that the boy has understood the shortcomings of logic, adopted him.The queen hailed the boy as "Alavandhaar"- the saviour. In other versions of the legend, he is given half the kingdom. There is no historical record to show his reign so it is possible that this happened in a smaller village rather than the kingdom of Pandya.
After years of rule, Mannakal Nambi tricked him into visiting the temple of Ranganatha. There, he had an epiphany and gave up the material duties of a king and became a sanyasin embracing saranagati. He composed the chatushloki and Strotra Ratna at that spot. Mannakal Nambi handed over the reins of Natha Muni's school including the collected Divya Prabandha and renamed him Yamuna Muni or Yamunacharya.
As he grew older, he was perturbed that he could not finish the tasks he had set for himself and asked Ramanuja to visit him. However, he died before he could talk with Ramanuja. Srivaishnavite devotees say that his corpse had curled three fingers and when Ramanuja saw these, he understood the tasks and promised to finish them whereupon the fingers straightened.
The names of Parasara and Veda Vyasa, should be commemorated on the earth by giving it to a person worthy to bear it. Compose a commentary on Tiruvaymozhi of Nammalvar the most prolific of Alvars. Compose a commentary on Upanishads, Vedanta Sutras and Bhagavad Gita.