You may have heard there's a new Pope, who happens to have a degree in math. Did you know an earlier Pope, Sylvester II (Gerbert of Aurillac) was one of the major shapers of math? He wrote five influential math books.

Let's start with the Codex Vigilanus (976), which introduced ġubār numbers:

A student of Gerbert (Pope Sylvester II), Bernelinus of Paris, put these numbers into Liber Abaci.

Later, Leonardo of Pisa (Fibonacci), wrote his own Liber Abaci (1202) and wrote the numbers like this (photo by David Singmaster):

... which looks very similar.

Scotty Brennan did a slideshow on Gerbert of Aurillac and showed this summary of the development of numbers as seen in their sources:

Of course, these days we see them like this:

Grid[Partition[RandomSample[ResourceFunction["CompareFonts"]["1234567890 ",FontSize->14],35],5]]

Pope Sylvester II also wrote extensively about Geometry, primarily using Euclid's Elements as a source.