Maya nobility performed bloodletting sacrifices to strengthen a 'dying' sun god during solar eclipses 

 The Maya created a complex calendar system to regulate their world — one of the most accurate of pre-modern times. 

https://cdn.mos.cms.futurecdn.net/6R92B7x9zUFFnqJKW2Wcr9.jpg

https://www.space.com/maya-nobility-bloodletting-sacrifices-during-solar-eclipse