att.sortable provides attributes for elements in lists or groups that are sortable, but whose sorting key cannot be derived mechanically from the element content. [1 The TEI Infrastructure]
a sequence of characters which, when sorted with the other values, will produced
the desired order; specifics of sort key construction are application-dependent.
David's other principal backer, Josiah ha-Kohen <index indexName="NAMES"> <term sortKey="Azarya_Josiah_Kohen">Josiah ha-Kohen b. Azarya</term> </index> b. Azarya, son of one of the last gaons of Sura was David's own first cousin.