The Yuan Dynasty of China had several inventions and accomplishments during their reign (1271 to 1368).
As far as concepts and inventions, the Yuan Dynasty was really the first in China to use and print paper currency (money).
They also made a very accurate calendar. It was 365 days long and was used for over 350 years.
Math was also a great accomplishment for the Yuan Dynasty. Chinese Algebra was at a high level at this time.
Like currency printing, the Chinese of this period also invented a moveable type printing system. This was a terrific invention because it was really efficient and made books more accessible to all types of people. Farmers really benefited from this invention, because they were able to access agricultural books that helped them with farming.