From 1824 to 1826, Rottiers made a journey through the Mediterranean, paid for by the ministry. This journey was Rottiers' own idea, and the purpose of it was to buy antiquities. Reuvens, who was not very enthusiastic about this project, was asked to provide Rottiers with instructions. During these travels Rottiers complained a lot, and for a while failed to produce any real results. The ministry had to go as far as send him an official warning to stop using government funds for anything other than buying antiquities. Plans of Rottiers' to start his own excavations were never discussed with Reuvens, and eventually Rottiers actually excavated on Melos. After this excavation Rottiers continued his travels and bought antiquities. During a lengthy stay on Rhodes, he studied and described the medieval architecture, large parts of which would later be destroyed, making the drawings commissioned by Rottiers invaluable.