The “Deutsche Forschungsgemeinschaft” (DFG) has been funding a research project of the “Institute for Research on the Septuagint and the Biblical Text” (ISBTF; www.kiho-wb.de/ISBTF) in Wuppertal for more than three years and thus making possible the in-depth-study of the textual history of Old Testament quotations in the New Testament and the quoted passages from the LXX. The textual history of New Testament quotations and their LXX counterparts is complex: Different textual traditions stemming from revisional processes as well as mutual interference between Old and New Testament transmission need to be taken into account. In this paper, some results of the LXX.NT research project are presented. The focus is on quotations from the Pentateuch (considering the LXX- and the NT-text) with special emphasis on Codex Ambrosianus, which partially presents a text closer to the New Testament than to the Old Greek. The presentation highlights the textual history of selected examples based on the general results of the Wuppertal project. Attention is also paid to graphical marks within the oldest codices (including Codex Ambrosianus) which suggest an awareness for intertestamental quotations within the first centuries. The examples demonstrate: The transmission of LXX and New Testament text came about independently, mutual interference should be considered exceptional. The New Testament quotations are – like the variants presented by Codex Ambrosianus – autonomous witnesses for the plurality of the Greek Pentateuch text of the first centuries.