The relationship between inflectional case marking and the emergence of definite and indefinite articles has been widely invoked but rarely tested quantitatively. This study provides a large-scale statistical evaluation across 94 Indo-European languages. It uses Bayesian logistic regression models that account for phylogenetic and spatiotemporal autocorrelation and integrate over phylogenetic uncertainty. The results establish a robust inverse association between case-inventory size and the presence of articles. Estimated probabilities indicate that lower case-inventory sizes are associated with higher probabilities of definite articles and, conditional on their presence, of indefinite articles. The posterior median predicted probability exceeds 0.5 at four cases for definite articles and between three and four cases for indefinite articles. These thresholds correspond to reduced case inventories composed primarily of grammatical cases. The presence of a definite article further increases the probability of an indefinite article independent of case-inventory size. The analysis shows that the observed association is compatible with direct, mediated, and common-cause accounts and does not uniquely identify a causal pathway. The study sharpens the empirical basis of the debate and identifies the causal and evolutionary questions that remain open.