From a historical point of view, 12 was simply the most practical number. Ancient traders loved the number 12. If you had 12 apples, you could easily share them between 2, 3, 4, or 6 people. If you had 10 apples, you could only share them easily between 2 or 5 people. This made base-12 the perfect system for markets and trade, which naturally bled into how they measured time.