Among his known works are 17 books of songs, odes, plantos, octaves, etc. Mostly written in Spanish, his work was eminently of a moral and ascetic nature. The compilation Obras de Don Manoel de Portugal ("Works by Dom Manuel of Portugal"), published in 1605, ended with a Tratado breve da oração ("Brief treaty on prayer") written in Portuguese. In the treaty, Dom Manuel summarizes the doctrines of the greatest Christian thinkers about prayer.
Dom Manuel was esteemed by his peers: the poet Sá de Miranda dedicated to him the eclogueEncantamento, and Luís de Camões, in Ode VII, considered him as deserving "immortal glory".[3] His poem Aquella voluntad que se ha rendido, written around 1555 for his beloved Dona Francisca de Aragão, was set to music and included in the songbooks of Elvas and Belém.