Divine Asterisk

The asterisk was already in use as a symbol in ice age cave paintings. There is also a two-thousand-year-old character used by Aristarchus of Samothrace called the asteriskos, ※, which he used when proofreading Homeric poetry to mark lines that were duplicated. Origen is known to have also used the asteriskos to mark missing Hebrew lines from his Hexapla. The asterisk evolved in shape over time, but its meaning as a symbol used to correct defects remained.

In the Middle Ages, the asterisk was used to emphasize a particular part of text, often linking those parts of the text to a marginal comment. However, an asterisk was not always used.

One hypothesis to the origin of the asterisk is that it stems from the 5000-year-old Sumerian character dingir, 𒀭, though this hypothesis seems to only be based on visual appearance. 

—Wikipedia