Icelandic makes use of different morphosyntactic patterns for different kinds of possessive relations both in predicative and attributive possession. The fact that this differentiation is at least partly motivated by the semantics of the possessum suggests an alienability split in the Icelandic possession system (Stolz 2008). There are various approaches to explain the formal distinctions in the system, one of them depending on grammaticalization processes. Following this approach, a diachronic perspective needs to be taken in order to understand how splits arise. Accordingly, this paper presents the results of a corpus-linguistic and frequency-based analysis of the attributive pronominal possessive system of Icelandic. The most significant finding to emerge is that splits in the possessive system do not only manifest in a different synchronic behaviour but also in different degrees of susceptibility to language-internal and/or contact-induced changes.