The nation of lost one-third of its population from the black death.

Europe

Explanation:

Europe suffered the most devastating death after coming to contact with the bubonic plague. The plague for the first time began in Asia and later, moved to Europe. The epidemic first appeared at Messina, in Sicily in 1347.  Europe came into contact with the plague through the trade route that connected the Black Sea to the Mediterranean Sea. It is estimated that it killed one-third of the European population. According to Ole Jorgen Benedictow's book 'The Black Death, 1346-1353: The Complete History', estimates 50-60% of the population died in Europe during the Black Death,  which is more than the one-third population.

the authority to tax.