This paper discusses the hitherto virtually unknown Byzantine cave monastery in the Ilgarini mağarası in the district of Pınarbaşı/Kastamonu based on its building remains, graffiti (mostly crosses), burials and notable finds. The remains were recorded during two brief surveys in 2012 and 2022. To shed light on the history of the site, an attempt is made to contextualise it within the mountainous regions of Middle Byzantine Paphlagonia, as well as with Middle Byzantine texts that relate to monasticism and might refer to the site. Research produces tentative evidence that the Ilgarini mağarası may be identified with the Chryse Petra known from several Byzantine texts, most prominently the Life of St Nikon Metanoite.