The original composition of the Catena on Exodus was expanded twice in the course of time. The most recent addition is a series of quotations from Severus of Antioch, which was recently published in a separate volume (TEG 9). The other was inserted into one branch of the Catena tradition only (the so-called secondary tradition) and consists of a collection built up around the Quaestiones of Theodoret of Cyrrhus. Named after the manuscript in which it first came to light, the Collectio Coisliniana contains twenty-six texts, most of them attributed to Diodore of Tarsus. In the primary tradition, only the first half of the Book of Exodus (up to and including the Canticle of Moses) of the original Catena is preserved. This text is published here along with the parallel (and previously unpublished) passages in the ‘Commentary’ of Procopius of Gaza. The remaining part of the Catena, known only in the secondary tradition, will be published in the third and final volume.