Question: What was the former name of the birthplace of Lou Yun?

full_context: Document 1: Lou Yun: Lou Yun began gymnastics training at the Hangzhou Sports School for Amateurs, and in the same year he also entered the provincial sports school of Zhejiang. He was selected for the National Gymnastics team in 1977. Known for his specialty in the vault, he won the 1987 World Championships in that event, in addition to his two gold medals.
Document 2: Gymnastics: In the vaulting events, gymnasts sprint down a 25 metres (82 ft) runway, jump onto a spring filled board or perform a roundoff, or handspring entry onto a springboard (run/ take-off segment), land momentarily, inverted on the hands on the vaulting horse, or vaulting table (pre flight segment), then propel themselves forward or backward, off of this platform to a two footed landing (post flight segment). Every gymnast starts at a different point on the vault runway depending on their height and strength. The post flight segment may include one or more multiple saltos or somersaults, and/or twisting movements. A round-off entry vault, called a Yurchenko, is the most common vault in elite level gymnastics. When performing a yurchenko, gymnasts "round-off" so hands are on the runway while the feet land on the springboard (beatboard). From the roundoff position the gymnast travels backwards and executes a backhandspring so that the hands land on the vaulting table. The gymnast then blocks off the vaulting platform into various twisting and/or somersaulting combinations. The post flight segment brings the gymnast to her feet.
Document 3: Nanjing: The city of Nanjing was razed after the Sui dynasty took over it. It renamed Shengzhou (昇州) in Tang dynasty and resuscitated during the late Tang. It was chosen as the capital and called Jinling (金陵) during the Southern Tang (937–976), a state that succeeded Wu state. It renamed Jiangning (江寧) in Northern Song dynasty and renamed Jiankang in Southern Song dynasty. Jiankang's textile industry burgeoned and thrived during the Song dynasty despite the constant threat of foreign invasions from the north by the Jurchen-led Jin dynasty. The court of Da Chu, a short-lived puppet state established by the Jurchens, and the court of Song were once in the city. Song was eventually exterminated by the Mongol empire under the name Yuan and in Yuan dynasty the city's status as a hub of the textile industry was further consolidated.
Document 4: Zhejiang: Zhejiang, as the heartland of the Jiangnan (Yangtze River Delta), remained the wealthiest area during the Six Dynasties (220 or 222–589), Sui, and Tang. After being incorporated into the Sui dynasty, its economic richness was used for the Sui dynasty's ambitions to expand north and south, particularly into Korea and Vietnam. The plan led the Sui dynasty to restore and expand the network which became the Grand Canal of China. The Canal regularly transported grains and resources from Zhejiang, through its metropolitan center Hangzhou (and its hinterland along both the Zhe River and the shores of Hangzhou Bay), and from Suzhou, and thence to the North China Plain. The débâcle of the Korean war led to Sui's overthrow by the Tang, who then presided over a centuries-long golden age for the country. Zhejiang was an important economic center of the empire's Jiangnan East Circuit and was considered particularly prosperous. Throughout the Tang dynasty, The Grand Canal had remained effective, transporting grains and material resources to North China plain and metropolitan centers of the empire. As the Tang Dynasty disintegrated, Zhejiang constituted most of the territory of the regional kingdom of Wuyue.
Document 5: Nguyễn Lộc: In his younger years he trained in traditional Vietnamese martial arts. In 1938, grandmaster Nguyễn introduced his style "Vovinam" to the public. After a demonstration in 1939 in Hanoi, Vovinam quickly spread across the country, and internationally to the Vietnamese diaspora via France. However the French banned the movement in 1942.
Document 6: Zhejiang: Despite the continuing prominence of Nanjing (then known as Jiankang), the settlement of Qiantang, the former name of Hangzhou, remained one of the three major metropolitan centers in the south to provide major tax revenue to the imperial centers in the north China. The other two centers in the south were Jiankang and Chengdu. In 589, Qiangtang was raised in status and renamed Hangzhou.
Document 7: Gymnastics: The technical rules for the Japanese version of men's rhythmic gymnastics came around the 1970s. For individuals, only four types of apparatus are used: the double rings, the stick, the rope, and the clubs. Groups do not use any apparatus. The Japanese version includes tumbling performed on a spring floor. Points are awarded based a 10-point scale that measures the level of difficulty of the tumbling and apparatus handling. On November 27–29, 2003, Japan hosted first edition of the Men's Rhythmic Gymnastics World Championship.
Document 8: Lou Yun: Lou Yun began gymnastics training at the Hangzhou Sports School for Amateurs, and in the same year he also entered the provincial sports school of Zhejiang. He was selected for the National Gymnastics team in 1977.  Known for his specialty in the vault, he won the 1987 World Championships in that event, in addition to his two gold medals.
Document 9: Zhejiang: Valleys and plains are found along the coastline and rivers. The north of the province lies just south of the Yangtze Delta, and consists of plains around the cities of Hangzhou, Jiaxing, and Huzhou, where the Grand Canal of China enters from the northern border to end at Hangzhou. Another relatively flat area is found along the Qu River around the cities of Quzhou and Jinhua. Major rivers include the Qiangtang and Ou Rivers. Most rivers carve out valleys in the highlands, with plenty of rapids and other features associated with such topography. Well-known lakes include the West Lake of Hangzhou and the South Lake of Jiaxing.
Document 10: Wu Jiani: Wu was born in Shanghai. She started gymnastic training in 1973, and was admitted into Shanghai gymnastic team in 1976, and Chinese national team in 1977.
Document 11: Ri Se-gwang: Ri was the first North Korean ever to win a gold medal on vault at the Asian Games, where he performed solidly at the 2006 Asian Games and was the first one for North Korea on that apparatus. He later went on to win a bronze medal on vault at the 2007 World Artistic Gymnastics Championships.
Document 12: Nanjing: Being one of the four ancient capitals of China, Nanjing has always been a cultural centre attracting intellectuals from all over the country. In the Tang and Song dynasties, Nanjing was a place where poets gathered and composed poems reminiscent of its luxurious past; during the Ming and Qing dynasties, the city was the official imperial examination centre (Jiangnan Examination Hall) for the Jiangnan region, again acting as a hub where different thoughts and opinions converged and thrived.
Document 13: Li Kun: Li Kun started his professional football career in 2001 at top tier military club Bayi Football Team after graduating from their youth team. He initially started out as a striker and would go on to make eight league appearances within his debut season. The following season would see Li progress to become a squad regular within the team while the club experienced a disappointing season and finished thirteenth within the league. By the 2003 league season Bayi were struggling to adopt to the financial requirements required for full professionalism within Chinese football and when the team experienced relegation at the end of the season the club was disbanded.
Document 14: Nanjing: Since the Three Kingdoms period, Nanjing has been an industrial centre for textiles and minting owing to its strategic geographical location and convenient transportation. During the Ming dynasty, Nanjing's industry was further expanded, and the city became one of the most prosperous cities in China and the world. It led in textiles, minting, printing, shipbuilding and many other industries, and was the busiest business center in East Asia. Textiles boomed particularly in Qing dynasty, the industry created around 200 thousand jobs and there were about 50 thousand satin machines in the city in 18th and 19th century.
Document 15: Nanjing: During the period of North–South division, Nanjing remained the capital of the Southern dynasties for more than two and a half centuries. During this time, Nanjing was the international hub of East Asia. Based on historical documents, the city had 280,000 registered households. Assuming an average Nanjing household had about 5.1 people at that time, the city had more than 1.4 million residents.
ground_truth: Qiantang
sub_queries: Lou Yun >> place of birth Answer: Hangzhou
What was the former name of Hangzhou ? Answer: Qiantang