Indonesia is made up of about 17,508 islands, making it the largest archipelagic country in the world. Indonesia has the largest Muslim population in the world and the fourth most populous country in the world.
Today, Indonesia is the largest economy in Southeast Asia and the most powerful country in Southeast Asia. 
The current Indonesia can be regarded as the revival of the Guawa Empire. In the 14th century, the Majapahit Empire on the island of Java was the largest power in Southeast Asia. At its peak, the country reached the south of Thailand in the north, the Strait of Malacca in the west, Papua New Guinea in the east, and Australia in the south. 
The territory of the Javanese Empire at its peak. The Majapahit Empire was rich in products and had a well-developed agriculture.
The empire also controlled important maritime routes, and gained a great deal of wealth from China, India, and the Arab region.
The empire was politically unified, economically prosperous, culturally brilliant, and militarily powerful. 
The capital of the Majapahit Empire: Banyan Gate in Bitter Orange City) At its peak, the Majapahit Empire had a powerful navy and army. Its navy fleet consisted of hundreds of warships, while its army consisted of well-trained infantry, cavalry, and war elephants. The military strength of the empire allowed it to resist foreign invasions and expand into the surrounding areas. 
Young King's Gate).Why did a maritime empire in Java collide head-on with the Yuan Dynasty, a land empire? Here's the thing, the Mongol Empire in the 13th century set foot in Europe and Asia, north and south of the earth. After Kublai Khan ascended the throne and established the Yuan Dynasty, the Mongol Empire was broken down into four khanates and the Yuan Empire.
The four khanates occupied the north, so the strategic focus of the Yuan dynasty gradually shifted from the mainland to the sea. 
In the face of the vast and boundless ocean, the consciousness of sea power of the people of the Yuan Dynasty began to sprout.
Kublai Khan set up Shanghai, Qingyuan, Quanzhou, Hangzhou, Wenzhou and other cities to govern the coastal port business, and later made two eastward expeditions to Japan, and continued to conquer Champa, Annam, and Java in the south. At that time, although the navy of the Yuan Dynasty was the most powerful navy in the world, the navy of the 13th century was still not an opponent of geographical advantages and time. 
The Yuan Dynasty was defeated by a typhoon.
The Yuan Dynasty's two expeditions to Java also ended in failure.
First expedition to Java. In 1292, Kublai Khan sent an army of Mongols and Han Chinese on an expedition to the state of Java. This army was led by Shi Bi and Yihei Lost, with a strength of about 20,000 people. The Yuan army set out from Quanzhou, sailed to the island of Java, and landed in the eastern part of the state of Java. The state of Java was ruled by Shin Ha Sha Li, and when he learned of the Yuan army's attack, he immediately organized an army to resist. The Javanese army took advantage of the favorable terrain of jungles and swampy areas to wage guerrilla warfare against the Yuan army. The Yuan army was not familiar with the local environment, was not accustomed to the water and soil, and the disease was rampant, and the combat effectiveness was greatly reduced. After months of fierce fighting, the Yuan army suffered heavy losses, and Shi Bi and Yihei were also captured by the Javanese army. In 1293, the Yuan army was forced to withdraw to China, and the first expedition to Java ended in failure. 
Second Expedition to the State of JavaIn 1299, Kublai Khan again sent an army on an expedition to the state of Java. This army consisted of the Xue army and the Han army, with a strength of about 30,000 people. The Yuan army, led by Instigation, set out from Quanzhou, sailed to the island of Java, and landed in the western part of the state of Java. On the Javanese side, Shin Ha Sari has died, and his son Jayakawila has succeeded to the throne. Having learned the lessons of the last war, Jayakawila strengthened coastal defenses and organized armies to build fortifications along the coast. After the Yuan army landed, it encountered stubborn resistance from the Javanese army. The Javanese army took advantage of its geographical advantages to launch guerrilla warfare against the Yuan army. The Yuan army was unable to attack for a long time, its morale was low, and its combat effectiveness was seriously damaged by disease and supply difficulties. In 1300, the Yuan army was forced to withdraw to China, and the second Java expedition ended in failure. 
The two expeditions of the Yuan Dynasty failed to conquer Java for the following main reasons. 1. Geographical factors: Java is located in the tropics, with dense jungles and swamps, which is not conducive to cavalry combat. 2. The Yuan army came from the north, did not adapt to the tropical climate, and was easy to adapt to the soil and water.
3. Malaria and other tropical diseases are prevalent in Java, causing the disease to be rampant, and a large number of soldiers are infected and die.
4. Cross-sea expeditions, difficult to supply in the later stage. 5. The Javanese army and people united and launched a stubborn resistance, which caused a huge ** to the Yuan army.
The failure of the Yuan expeditions to Japan and Java proved that the Yuan Empire did not have the technical conditions to conquer tropical maritime regions. Later, Zheng He of the Ming Dynasty was also unable to profit from the seven voyages to the West, also because the technical conditions were not available. 
Western sailing ships in the Age of Discovery. ）
The Europeans began the Age of Discovery, and the innovation of nautical instruments, the innovation of ship design, the improvement of nautical knowledge and skills, and the organization and training of nautical personnel laid a solid foundation for European navigation in the Age of Discovery.