This study provides a survey of the constructions of verbal nouns with prepositions that are used in a significant way, such as creating syntactic and semantic contexts not found with ordinary nouns. Particular emphasis is placed on constructions serving to denote tense, mood and aspect. Also some syntactic contexts involving verbal nouns as objects are examined. This material has been collected primarily from Old and Middle Irish texts, but some reference is made to Modern Irish where this seems helpful in order to illustrate developments. The observations made are compared to findings on the use of verbal nouns in a closely related language, Middle Welsh, and an unrelated, non-Indo-European language, Basque. The discussion of the Medieval Irish material is followed by the evaluation of an illustrative corpus of Middle Welsh data and available descriptions of Welsh verbal nouns. Parallel constructions in these Insular Celtic languages are then brought together in order to assess which prepositional verbal noun constructions might have been a feature of Insular Celtic. Data from Basque is compared to the findings for Insular Celtic. The results seek to identify the language specific features of Old Irish verbal nouns and a common core of verbal noun usage in Insular Celtic as opposed to other usages adopted by a non-Indo-European sample language.