 Gorresio carefully collated manuscripts held at the Bibliothèque royale in Paris, and later at the Royal Society and East India House in London, where he arrived in 1841.With the advice of Horace Hayman Wilson, a professor of Sanskrit at Oxford University, Gorresio studied various commentaries on the Ramayana, notably the "Manohara" of Lokānatha Cakravartin and the "Rāmāyaṇa Tilaka" of Ragunātha Vācaspati, as well as commentaries by Kullūkabhaṭṭa and earlier research by August von Schlegel.The introduction to the first volume of Gorresio's series accurately set out the contradictions and interpolations that accrued over the ages in the Ramayana text.