The paper examines 30 instances of Psalm 129 in 16th-century English devotional manuals printed during the reign of the first three Tudor monarchs. The objective of the study is to detect relationships between the analysed texts and compare them to available Psalter translations to determine textual affinities. This is achieved by applying similarity measurements which can capture intertextual relations in mathematical terms. The obtained results are subsequently verified against the available textual and philological knowledge, which corroborates the similarity scores of individual texts. In the single instance where similarity scores seem to be defied by the information provided in the literature on the topic, textual analysis proves the applied method right. The examination presented in the paper shows that English devotional practices in the turbulent period when they were emerging were much more complex than the purely denominational differences between Catholics and Reformers (often misconceived from the present-day perspective) might suggest.