Rank 5: Ptolemy
The second Chocolate Frog card that Ron is missing for his collection is that of Ptolemy. Claudius Ptolemy was a Greek scientist from the 2nd century AD who is mainly known for his works on astronomy, geography, and mathematics.
Although not much more than his name is mentioned in Harry Potter, we do know that Hogwarts offers subjects such as Astronomy and Arithmancy, a combination of math and divination. It is therefore not difficult to imagine that Ptolemy became famous in both the Muggle and wizarding worlds for his research.
