In biblical textual criticism, these text critical marks are associated most famously with Origen, who employed them in his 6-column work called the Hexapla. Although the Hexapla no longer survives as a whole, it was immensely influential on later Greek translations of the Hebrew Bible. The columns of Origen’s Hexapla contained an unpointed Hebrew text (column 1), a vocalised Hebrew text in the Greek script (column 2), three earlier Greek translations or versions (Aquila, Symmachus, and Theodotian; columns 3, 4, and 6), and Origen’s own “fifth column” which was based on the Septuagint (LXX) translation of the Hebrew text. It was in this fifth column that Origen employed the asterisk and obelos, amongst other text critical marks, in order to reconcile the LXX with the Hebrew text.
Due to the fact that Origen assumed (probably wrongly) that the Hebrew text was older and more original than the Hebrew Vorlage (original) reflected in the LXX, he treated the Hebrew text as the correct text. As a result:
1. Words in the the ‘original’ Hebrew text which were lacking in the LXX were inserted in Origen’s fifth column, and marked with an asterisk (*). The asterisk was placed before the first inserted word, and a metobelos was placed at the end of the last inserted word. For example (from Ernst Würthwein):
Because Origen considered the Hebrew text to be original, the asterisk indicated a correction to the LXX.
2. Words in the Greek versions which did not appear in the ‘original’ Hebrew text were considered spurious or corrupt additions to the Greek, and marked with an obelos (÷ or † or variations). The obelos was placed before the first word considered to be spurious, and a metobelos was placed at the end of the spurious section. For example (again, from Ernst Würthwein):
Because Origen considered the Hebrew text to be original, the obelos indicated a corruption in the LXX.
In addition, Origen added some of his own additions to the fifth column. And just to complicate matters further, sometimes he didn’t bother to mark his additions with an asterisk.
Origen’s employment of the obelos and asterisk was itself based on the classical texual criticism carried out at Alexandria. These and other text critical marks are often referred to as ‘Aristarchian’, named after Aristarchus of Byzantium the chief librarian at Alexandria (ca. 180 BCE). In fact the obelos was used a century earlier by the first chief librarian, Zenodotus (ca. 284 BCE), known as the father of textual criticism, who had earlier marked what he considered to be Homeric corruptions with the obelos. However, Zenodotus was often quite subjective when he determined Homeric corruptions. Often he would mark the text as corrupt when it seemed to him to be too vulgar or inappropriate, which is hardly a sound basis for textual criticism. At a later time, the chief librarian Aristophanes of Byzantium (ca. 200 BCE) added the asterisk to the list of critical markers, to denote the insertion of text from another context. So Origen’s method of critically marking the LXX is dependent on the system earlier worked out at Alexandria.
As a last observation, the Greek word obelos means a ‘pointed pillar’. Much of the time, Obelix is depicted carrying a pointed pillar, or menhir. The Greek asterískos means a ‘little star’, which seems to apply well to the diminutive hero, Asterix. Or is there an asterisk formed on his gourd of magic potion? Those funny old Gauls!