The Angel Sandalfon
“The theory of the intelligible points is connected with the reinterpretation discussed previously (p. 259) of the ideas as spiritual atoms and their application to the sefiroth. From these and similar Provençal sources, this theory then made its way to the kabbalists in Castile, above all to Isaac Cohen and Todros Abulafia, and from there to the author of the Zohar.
The same hierarchical structure is expounded regarding the origin and still more the place of the supreme beatitude of the prophets, the hagiographers, and the mystical scholars in the description of the seven palaces of the lowest heaven, which comes immediately after the aforementioned account of the ritual for the conjuration of the Prince of the Torah.
The sefirotic symbolism is here presupposed as self-evident. The palaces begin with the lowest and ascend in rank, just as do the archons in charge of them. The highest rank is held not by Metatron, who rules over the sixth palace, but by Sandalfon, whose name is associated with the secret of the conquest of matter by form. This is the oldest source of this mystical etymology of Sandalfon, and it was in use later among many Spanish kabbalists.”
Gershom Scholem, Origins of the Kabbalah, pp. 361-2.