Jnaniswara is one of those legendary medieval Hindu men that are so hard to materialize out of time's mists. Prior to the 19th century, when a sense of biography blossomed in India, a chronicle of a great man's life was non-existent. The flotsam of folk legend, a scriptural reference and maybe a stone-etched royal decree were all there was to assemble a flesh-and-blood life. Where was the James Michener to write thousand-page tomes – like his latest book, Alaska – on Hindu men and land?

Jnaniswara, or Jnanadeva as he is also known, is a name familiar to all Hindus of Maharashtra, India. He is idolized with the same transfiguring awe as Chaitanya for the Bengalis, Gorakhnath for the Nepalese, Manikkavasagar for the Tamils, Allama Prabhu for the Karnataka Lingayats. Most Hindus have at least heard the name Jnaniswara and know his principle accomplishment was a wide-ranging commentary on the Bhagavad Gita in Marathi, the language of Maharashtra. It is called Jnaniswari.

It is the 13th century. Europe is recovering from the Dark Ages, St. Francis of Assisi is breathing renunciation back into a power-and-riches encrusted Christian Church. At the same time that Marco Polo is trudging across the perilous Gobi Desert into Kublai Khan's China, a young king comes to power in Maharashtra – a kingdom slicing in from India's West-central seaboard. In the year 1271 at the capital city of Devagiri, Ramadevarava is crowned. It is a time when Marathi scholarship and culture is at its zenith, though this "Golden Age" would soon be extinguished in 1318 by the Muslim military Juggernaut. The great tidal wave of Siva and Vishnu bhakti movements had swept over India. Under its power, the tightly guarded philosophical bastions of the brahmin priests and monks had crumbled. Scriptural reasoning for the privileged gave way to divine feeling for the masses.

Maharashtra was a cradle for two forms of Vaishnavism: Krishna and Vithoba. And tucked away in forested valleys and mountain aeries were the Saiva Natha yogis, the lords of yoga. In this setting, purportedly at the village of Alandi, dwelled Jnaniswara's family, the Vitthalpants of brahmin stock. It was a precociously spiritual family. Like the Kennedys of politics or the Khans of music, Jnaniswara's two brothers and one sister distinguished themselves as great yogi mystics and bhakta poets.

Before the children were born, the father, Vitthalpant, gravitated to a renunciate's life. He left his wife to seek initiation from a guru in distant Kashi (Benares). Keeping his marriage secret, he took sannyas. The guru found out and sent him back to Alandi to fulfill his family obligations. The Alandi brahmin community turned on him and forced the ostracized couple to live on the village outskirts. Here the children were born, raised and instructed in Sanskrit as well as Marathi (a derivative of Sanskrit) literature. The sons, barred from the sacred thread ceremony, became known as outcaste brahmins.

Jnaniswara's elder brother, Nivrittinatha (note the Natha suffix) had joined the secret enclaves of the Saiva Natha yogis. When Jnaniswara was in his teens, he was initiated into the Natha lineage by his brother. Nivrittinatha also initiated the youngest brother, becoming the guru to them both. For several years Jnaniswara was absorbed in the kundalini yoga disciplines of the Nathas, climbing to rarified heights of superconscious vision.

But Jnaniswara was not to remain a yogi ascetic. He was a hybrid man: a Saiva yogi grafted onto Vaishnavite brahmin stock. And his interest in preaching through the idiom of Marathi was overwhelming. It's unknown when he began the Jnaniswari. It was finished in 1290. The Bhagavad Gita itself is 70% transplanted Upanishads. Jnaniswara exploded the 700 verses of the Gita into a rambling, entertaining and very sublime commentary 9,000 verses long. The sections on yoga are unusually good and he often inserts his brother/guru into the narrative. Jnaniswara was now in his early twenties. Other philosophical inquiries – including a brilliant exigesis on the Upanishads – and devotional hymns followed in a flurry of expression, creating the sense of Jnaniswara's urgently needing to finish his work. Then, just as quickly as his exposition started, there is silence. Still in his twenties, he returned to Alandi. According to legend, he had himself entombed alive while in a state of yogic samadhi.