manual. About 400 BC the crossbow was invented in China. Gunpowder was probably invented around the year 900 AD. It was used for rockets, grenades and bombs that were placed against the wooden gates of enemy cities. Chinese Houses Rich people lived in large wooden houses arranged around a courtyard. Roofs were typically of tiles and were built in a curved shape. However even in a rich house there was little furniture but rich people were very fond of their gardens. Poor people lived in hovels of perhaps 2 rooms. Roofs were often thatched and furniture was very basic such as wooden benches.