Melpathur Narayana Bhattathiri (Malayalam: ? ; 1560-1646/1666), third student of Achyuta Pisharati, was a member of Madhava of Sangamagrama's Kerala school of astronomy and mathematics. He was a mathematical linguist (vyakarana). His most important scholarly work, Prkriya-sarvawom, sets forth an axiomatic system elaborating on the classical system of Panini. However, he is most famous for his masterpiece, Narayaneeyam, a devotional composition in praise of Guruvayoorappan (Krishna) that is still sung at Guruvayoor Temple.
Bhattathri was from Melpathur, on the north banks of Bharathapuzha River, close to the holy town of Thirunavaya, near Tirur, that was famed as the theatre of the Mamankam festival. He was born in 1560 in a pious Brahmin family, as the son of Mathrudattan Bhattathiri, a pandit himself. Bhattathiri studied from his father as a child. He learned the Rig Veda from Madhava, Tharka sastra (science of arguments in Sanskrit) from Damodara and Vyakarana (Sanskrit grammar) from Achyuta Pisharati. He became a pandit by the age of 16. He married his guru Achuta Pisharati's niece and settled at Thrikandiyur near Tirur.
He was one of the last mathematicians of the Sangamagrama school, which had been founded by Madhava in Kerala, South India and included among its members: Parameshvara, Neelakanta Somayaji, Jyeshtadeva, Achyuta Pisharati, Melpathur Narayana Bhattathiri and Achyuta Panikkar. It flourished between the 14th and 16th centuries and the original discoveries of the school seems to have ended with Bhattathiri.
It seems that he had a younger brother named after his father (Mathrudattan Jr.,). One of the manuscripts of Narayaneeyam says that it was copied by the author's yonger brother Matrdatta. The Melputtur family is now extinct and it is said that it was merged into the Maravancheri Thekkedathu family. 
The Narayaneeyam is a devotional Sanskrit work, in the form of a poetical hymn, consisting of 1036 verses (called 'slokas' in Sanskrit). It was written by Bhattathiri in 1586 AD and gives a summary of 18,000 verses of the Bhagavata Purana.
Pisharadi has been affected by rheumatism. Unable to see his pain, by yogic strength and by way of Gurdakshina, Bhattathri is said to have taken the disease upon himself and relieved his guru. To relieve Narayana of this disease, Ezhuthachan, a Malayalam poet and Sanskrit scholar hinted- "meen thottu koottuka" (start with the fish). On the face of it, the suggestion would seem offensive to an orthodox Malayali Brahmin, who are strict vegetarians. However, Bhattathiri, understanding the hidden meaning, decided to present the various incarnations of Vishnu starting with the fish, as narrated in the Bhagavata Purana in a series of Dasakas (groups of ten slokas). Upon reaching Guruvayur, he started composing one dasaka a day in the presence of the Lord. The refrain in last sloka of every dasaka is a prayer to him to remove his ailments and sufferings. Every day, he sang 10 shlokas on Sri Guruvayoorappan. Each set of 10 poems ends with a prayer for early cure. In 100 days he finished his compositions, and his condition gradually improved day by day. On 27 November 1587 when he finished the last dashakam ("Ayuraarogya Sowkhyam") he was completely cured. The 100th canto composed on that day gives a graphic description of this form of the Lord from the head to the foot. On that day he had a vision of the Lord in the form of Venugopalan. He was 27 then. He was a propounder of Purva Mimamsa, Uttara Mimamsa and Vyakarana.
The Chakorasandesa which was earlier than Narayaneeyam also refers to rheumatic patients going to the Guruvayoor Temple. Worship in the Guruvayoor Temple is considered to be sure remedy for all diseases. It may be because of this belief that Bhattathiri went to Guruvayoor.
While Narayana Bhattathiri was composing Narayaneeyam in Guruvayur temple, Poonthanam, another great poet who wrote in Malayalam, had also come there to worship Krishna. One day he took some of his Malayalam poem to Bhattathiri to correct them but was dismissed with the haughty remark that Poonthanam didn't know the correct meaning of words. After that god himself intervened by saying that he preferred Poonthanam's bhakthi than Bhattathiri 's scholarship. And then Narayanabhatta apologized to poonthanam and they became friends.
He wrote on diverse subjects including scientific ones.His works are:
Under the patronage of Cochin Vira Keralavarman (1601-1615 A.D) Melputtur wrote the Gosrinagaravarnana and Virakeralaprasasti.:164
It is said that Bhattathiri lived at least for 86 years, since his wish was to have a happy, healthy, long life as seen at the end of Narayaneeyam. One poem says that he lived for 106 years, and accordingly he should have died in 1666. But, 86 is considered more reliable. Accordingly, he lived in many places after his cure of rheumatism, like Kochi, Ambalapuzha, Kozhikode and finally he settled in Mookkola near Changaramkulam in the present-day Malappuram district. He stayed in the Devi temple there for around 20 years, and he wrote his last work there. One day, after returning from Mookkola Temple, he collapsed and died instantly. Thus, he had a peaceful end as he wished.