A central concern in the study of language contact phenomena is the question of what linguistic features are more or less likely to be borrowed, and why. Pronominal borrowing, at least the direct borrowing of the phonological forms, is often ranked among the least common outcomes of language contact. This paper presents an extended case study of contact-induced changes in the system of person markers in several Mayan languages over nearly two thousand years of intense linguistic contact. The contact phenomena discussed appear to include the direct borrowing of pronominal ‘matter’, as well as the diffusion of structural and semantic ‘patterns’ that have led to a high degree of convergence in the overall system of pronominal reference in these languages. Possible social and linguistic motivations for the unusual contact-induced changes are considered.