Arcaicam Esperantom ("Archaic Esperanto") is a constructed language created to act as a fictional 'Old Esperanto', in the vein of languages such as Old English or the use of Latin citations in modern texts. It was created by Manuel Halvelik as part of a range of stylistic variants including Gavaro (a slang), Popido (a patois) and a scientific vocabulary closer to Greco-Latin roots.
The idea of an "old Esperanto" was proposed by the Hungarian poet Kalman Kalocsay who in 1931 included a translation of the Funeral Sermon and Prayer, the first Hungarian text (12th century), with hypothetic forms as if Esperanto were a Romance language deriving from Vulgar Latin.