Like the Roman Empire, the Guptan empire fell apart in the 500s AD. After that, India had a lot of kings ruling a lot of small kingdoms. In northern India, King Harsha ruled one of the small kingdoms. But after he died in the 600s AD, his kingdom fell apart into three even smaller ones. Most of southern India was divided among three kingdoms: the Chola, the Chera, and the Pandyas.
There were a lot of wars among these small kingdoms. But there was also a lot of great architecture and art during this time. The great university at Nalanda went on teaching students from all over Asia. India was part of the great Silk Road economy of the Middle Ages. So the Indian kingdoms were busy making and selling cotton cloth, glass beads, high quality steel, cinnamon, black pepper, pearls, salt, and sugar.
Traders took these products as far as Southeast Asia, China, Russia, Europe, and all over Africa. In return, the Indian kingdoms got rich on imported gold and silver. They bought horses, knotted wool carpets, and paper from Central Asia, silk and porcelain from China, glass from West Asia, furs from Europe, and ivory from East Africa.
As the Arabs expanded their empire and took over Iran from the Sassanians, they also conquered north-western India (what is now Pakistan). Pakistan was under Muslim rule by the early 700s AD. Many people living there converted from Buddhism, Christianity, or Hinduism to Islam.
By about 800 AD, though, some small kingdoms in northern India began to gradually get more power. Their kings came from a group of people called the Rajputs. So historians call their kingdoms the Rajput kingdoms. The Rajputs spent a lot of their time fighting off the Abbasid armies. They were trying to get past the Indus Valley to Delhi. Around 1000 AD, the Ghaznavids succeeded in repeatedly raiding and plundering northern India, but they didn’t rule it.
Also about 800 AD, the Chola kings began to conquer more and more of south India. They established a stronger kingdom than any in medieval northern India, with a professional army and navy. In 925, the Chola king Parantaka conquered Sri Lanka. Sri Lanka was a large island off the coast of India with strong steel-making and pearl-fishing industries. By 1000 AD, the Cholas controlled all of southern India.
Soon after that, with the Rajput kingdoms collapsing, the Cholas reached the Ganges River in northern India. The Chola kings and their trading ships also ruled or held power over a lot of Southeast Asia: Burma, Thailand, Malaysia and Indonesia. With all their money, the Chola kings built many great stone temples. But by the 1200s AD, the Chola kingdom lost power. Their old enemies the Pandyas came back and conquered them, establishing the Pandyan Empire.