Arnold Passow’s Popularia Carmina Graeciae Recentioris (1860) is a comprehensive collection of Modern Greek folk songs built upon fieldwork materials collected by his late father-in-law, Heinrich Ulrichs, alongside various published and unpublished manuscripts. The volume showcases the preservation of the Greek language and ancient traditions through Klephtic, romantic, and regional songs, offering valuable material for comparative linguistics from the Homeric era to modern times. To present the oral tradition systematically, Passow established standardized orthographic and phonetic rules for the demotic Greek text and accompanied the collection with an explanatory glossary of obscure, medieval, and foreign terms.