This thesis argues in favour of a corpus-based lexical analysis of the Peshitta by identifying language contact (Aramaic-Greek-Syriac) and corpus contact (LXX-P, T-P) on the one hand, and inner-Syriac developments on the other. Using case studies from Peshitta Genesis, the thesis responds to proposals of Septuagint or Targumic influence upon the Peshitta, and demonstrates that language contact and corpus contact represent two different processes that do not always follow the same route, and should therefore be distinguished. Ultimately, it asks about the contribution of Syriac lexemes for an understanding of the language of the Peshitta. The first chapter, Echoes of Greek Vocabulary and Septuagint in the Peshitta, examines the use of Greek loanwords in P-Gen and evaluates them in the larger context of the Greek and Syriac languages and the contact between them. The second part examines three types of relationship: places where P seems to follow all or part of a verse from LXX (Gen 4:8); where P and LXX both follow the presumed Hebrew text (Gen 31:19); and where P and LXX diverge significantly (Gen 38:14). The chapter contributes to the argument against a direct textual influence of LXX on P Genesis. The second chapter, Targums and Targumic Features in the Peshitta, examines the degree of relatedness between the vocabulary of P and T versions of the book of Genesis. It does not primarily aim to prove or disprove the textual dependence between P and T but instead examines examples where Syriac and Aramaic, as used in P and T, share common features and instances where they differ. In addition to lexicographical contributions, the chapter shows that Targumic features that sometimes appear in P do not necessarily reflect usage in T. The third chapter, Inner-Syriac Developments and the Peshitta, assesses the book of Genesis within the larger P corpus from the perspective of inner-Syriac developments. It illustrates issues of Syriac lexicography and demonstrates nuances of the meaning of Syriac lexemes used in P. Finally, the chapter explains that a corpus-based approach helps to situate better the use of lexemes in P within the history of Syriac language and lexicography.