Passing the River Aleph is drawn as a glyph-form for the Hebrew letter Aleph in the Transitus Fluvii, or Passing the River, one of three magical scripts Heinrich Cornelius Agrippa published in 1533, its name recalling a symbolic crossing of the Euphrates, rather than a script with independent letter meanings of its own; Aleph's own sound and classification, discussed elsewhere in this atlas, belong to the underlying Hebrew tradition.
As one of the Sefer Yetzirah's three mother letters, Aleph is paired with the element air and, in the same classical scheme, with the chest and a temperate climate, the chest being read as the seat of breath and voice, the medium every other sound depends on. Agrippa printed Transitus Fluvii alongside Celestial and Malachim in Book III of his Three Books of Occult Philosophy, Cologne 1533, without citing a source for any of the three, and no earlier witness to any of them survives; the name, recalling the crossing of the Euphrates, is generally read as a reference to the exodus of Abraham's household out of Mesopotamia, a symbolic passage from an older world into the one Hebrew tradition claims for itself. Of the other two mother letters, Mem is paired with water and Shin with fire, the three together forming the elemental triad the Sefer Yetzirah builds its whole cosmology upon.