In the National Archives in Kew, London, a treasure is kept which is of great importance for the history of the Dutch language: a collection of seventeenth-century letters written by men and women from various social backgrounds. Given the fact that much of the linguistic research of seventeenth-century Dutch has been perforce based on printed texts and linguistic data produced by a relatively small number of upper-class __ usually male __ writers, not much is known with certainty about the everyday Dutch of seventeenth-century lower- and middle-class people. The letters hidden in the National Archives can change this. In this dissertation, a corpus of 595 letters written between 1664 and 1672 is examined from a sociolinguistic perspective. The topics treated are: forms of address, reflexivity and reciprocity, negation, schwa-apocope, diminutives, and the genitive and alternative constructions. The case studies show that there was still a lot of variation in seventeenth-century Dutch and that some linguistic changes had not progressed as far in the everyday Dutch of __ordinary__ people as previous research has suggested. Furthermore, it is shown that gender and social class are important factors of influence on the seventeenth-century language use, especially when interpreted in terms of education and writing experience.“Letters as loot. Towards a non-standard view on the history of Dutch”, financed by the Dutch Organisation for Scientific Research (NWO).Descriptive and Comparative Linguistic