Shri Kulashekhara Alvar was the King of a princely state in Kerala. He was a great Devotee of Shri Rama. He was as much attached to Vishnu Bhaktas (Called Bhagavathas ) as to the Lord Himself. He was always in company with Devotees who came and stayed with him as guests. He liked their company and spent time in satsang singing the praise of the Lord. He was into this to the extent of overlooking the administration of the country which he left it to his ministers. The ministers in their turn were concerned that the King was showing apathy towards administration. In order to make him realise his mistake, the ministers planned to remove a valuable vessel of gold from the palace. They reported the matter to the King promptly. They also said that their suspicion of theft lay with the Bhagavatas who had free access to the King and palace. To this the king was sad that the Bhagavatas should be blamed. Without a second thought, he swore that Bhagavatas were innocent and pure. To prove this he put his hand inside a pot with a Cobra in it saying that he would be bitten if his statement ( that Bhagavatas were innocent ) is false. He was saved, showing his faith in Lord and His Devotees.
Alvar was very much devoted to Lord Shri Rama so much so that he saw Shri Rama in all the Deities he worshipped. It seems that once he was listening to a discourse on Ramayana. The lecturer was describing the battle of Shri Rama fighting alone with 14,000 Rakshasas in Janasthana. Alvar, on hearing this, got up excited and ordered his army to be ready to assist Shri Rama. Hurriedly, the lecturer explained that the Rakshasas were vanquished which cooled down.
His compositions is full of Bhakti Bhava. He is a good poet and he has composed 105 pasurams on Shrirangam, his Family Deity at Vithuvakkodu in Kerala, Thirumalai Thirupathi, Chidambaram etc. A sweet has to be tasted and words cannot give the experience!
Perhaps, he is the only Alvar who has written a Sanskrit Shloka, MUKUNDAMALA, in praise of Lord Krishna. This shloka is a classic in itself showing Alvar’s devotion, ecstasy he feels in chanting Lord’s names.
Source : http://vaishnavism.wordpress.com/category/kulashekara/