Vedanta Desika's Raghuveera Gadyam, which celebrates Lord Rama's valour, was composed when he was residing at the temple town of Thiruvendipuram in Tamil Nadu. The temple has icons of Rama, Lakshmana and Sita, and here Rama is seen as Kodandarama (with a bow in His hand).
Inspired by this, Desika wrote Raghuveera Gadyam, in which he focuses on Rama as a ‘veera' (warrior). But Rama was not an ordinary warrior. He was a ‘mahaveera.' He was not only capable of fighting courageously Himself, but could also lead an army. Thus, He combined in Himself the qualities of courage and leadership. Hence, Desika referred to Him as a ‘mahaveera,' said Vaduvur Veeraraghavachariar. In fact, Raghuveera Gadyam is known as Mahaveera Vaibhavam.
But why did Desika resort to the prose (gadya) form? Valmiki's Ramayana is in verse form. It could have been because in his work, Desika mainly wrote about Rama as a warrior, and for this, prose would be more suitable than verse. Another reason could be that Ramanuja himself had composed three works in prose — Sri Vaikuntha Gadyam, Saranagati Gadyam and Sriranga Gadyam. Desika even wrote a commentary on these works, and this commentary was called ‘Gadya Traya Bhashya.'
But even assuming Desika wanted to compose in prose form, because Acharya Ramanuja had done so, why did he write on Rama? It could be because the Ramayana highlights surrender (saranagati) as a means of moksha, and so Acharya Ramanuja himself had learnt the meaning of the Ramayana from his uncle Thirumalai Nambi.
Desika refers to the battle between celestials and demons, in which the celestials won with the Lord's help. Desika marvels at how Rama, even as a lad, protected the sacrificial fire of sages. He killed demons who did not allow them to perform sacrifices.
Sage Viswamitra taught Rama the secret of using powerful weapons. He also taught Rama and Lakshmana mantras that would help them conquer hunger and sleep. All of these only added to Rama's prowess, and these and other incidents, indicating Rama's courage, are marvelled at by Desika.