Questions about example sentences with, and the definition and usage of "Joseon"

A: × When Korea’s Joseon dynasty was under influence of China’s Ming dynasty, the fourth ruler, the Sejong the great, acknowledg Jang Yeong-sli’s talent, who was born as a peasant, and allow him to work at a the royal palace.
✓ When Korea’s Joseon dynasty was under the influence of China’s Ming dynasty, the fourth ruler Sejong the great acknowledged Jang Yeong-sli’s talent, who was born as a peasant, and allowed him to work at the royal palace.

× With his wide scientific knowledge and advanced technique, he invents the water clock, and the celestial globe one after the other.
✓ With his wide scientific knowledge and advanced techniques, he invented the water clock and the celestial globe one after another.

× These contributes to the people’s lives.
✓ Which were great contributions to people's lives.

× On the other hand, Sejong have the dream that the Joseon will be liberated from Ming and get independent and thinks about creating the Korean alphabet, hangul.
✓ Meanwhile, Sejong dreamt that Joseon will be liberated from Ming and become independent so he thought of creating a Korean alphabet, hangul.

× Despite their difference as night and day, they have been developing a special bond.
✓ Despite them being as different as day and night they have managed to develop a special bond.

× However, some of his subjects are afraid that Ming never allow their independence and will attack them, plots to tear them apart.
✓ However some of his subjects are afraid that Ming will never allow their independence and will attack them, plotting to tear them apart.

× One day, an terrible accident happened where the litter with Sejong are wrecked.
✓ One day, a terrible accident happens where the litter(?) with Sejong are wrecked.

I don't understand what 'litter' means in this context.
It's a little confusing because there are so many switches between present tense, past tense and future tense. I tried correcting the passage to the best of my ability. Otherwise, it's good.

A: Check the question to view the answer

A: "The Joseon dynasty becoming a Japanese colony was the result of mutual collaboration between western imperialist countries, Britain, the United States and Russia" is how i would word it.