The golden section (or golden ratio), famously, was used in antiquity, when the ancient Greeks built temples the proportions of whose parts - by accident or design - are often supposed to have fallen in the golden ratio.
It's worth pointing out right at the start that this wouldn't be a particularly good choice of calendar if you actually want to keep track of the year. The calendar is large (A2 size) but the days of the month occupy only a 1cm-high section of each page - and the day names aren't even included, just their numbers.
The paradoxes of the philosopher Zeno, born approximately 490 BC in southern Italy, have puzzled mathematicians, scientists and philosophers for millennia. Although none of his work survives today, over 40 paradoxes are attributed to him which appeared in a book he wrote as a defense of the philosophies of his teacher Parmenides.