Legend has it that when Mongol invaders captured the Song dynasty capital of Lin'an, loyal ministers fled with their seven-year-old emperor, Shi, and his five-year-old brother Bing, in a last-ditch effort to save the dynasty.
They headed south and arrived in what is now Kowloon in 1277AD. Alas, their time there was short. Shi soon died of sickness. With the Mongols closing in, the small band of loyalists refused to surrender. A minister scooped up the hastily crowned Bing and jumped off a cliff in Yashan, Canton.
Did the two boy emperors really come to Hong Kong? Historians still debate that.
But an archaeological excavation in Kowloon City renews hope of tracing the city's link to the brothers.
  An archaeologist hired by the MTR Corporation has unearthed thousands of clues, including two intact wells dating back to the Song (960-1279AD), or perhaps the Yuan, (1279-1368AD) dynasties.
"This is very important because the era matches the stories told from written records," says Professor Chiu Yu-lok, a historian at the Open University of Hong Kong. "They show the existence of mature settlements in the area in that period."
Independent Hong Kong historian Anthony Chan Tin-kuen says the discoveries offer a plausible explanation for the brothers' story.
"When the emperor and his people took refuge, they needed food and other materials and therefore would not stay in a barren place," he says. "The location of wells indicates a populous area in the Song-Yuan era."
The wells and other historical items were discovered during an archaeological survey of the area around the MTR's new To Kwa Wan station, part of the Sha Tin-Central railway link. The area was identified in 2008 as probably having high archaeological value.
Most of the items discovered have been moved to the government's depository for archaeological finds. One of the stone wells will be preserved on the site.
The station site is about 100 metres from the monument of Sung Wong Toi boulder, carved to commemorate the two boy emperors' refuge in Kowloon.
The site has yielded hundreds of treasures: house structures, burial sites, kilns, ditches, ponds and wells. Thousands of ceramic shards, coins and remnants of iron tools have also been unearthed.
Buried in layers up to four metres below the ground, the remnants show settlements from the Song dynasty to the early 20th century.
While some people are excited about the finds, two archaeologists are more cautious about its significance.
The man in charge of the excavation, Dr Liu Wensuo, of the Sun Yat-sen University in Guangzhou, declined to be interviewed.
Chinese University archaeologist Tracey Lu Lie-dan says it would be unscientific to draw any conclusions about the significance of the discovery as it will take a long time for the archaeological team to analyse the finds.
The latest find in Kowloon City may not be as surprising as the remnants of the Ma Wan excavation in 1997.
There, an archaeological team found 20 graves, proving that there had been a human settlement in Hong Kong in the late Neolithic to early Bronze Age (2000-1000 BC).
The Kowloon City site could fill a gap in the study of the city's role in the Song dynasty, a culturally important age that saw the invention of movable type and the rise of lyrical literature, even as the dynasty suffered from military and diplomatic weakness.
Despite knowing that the Song dynasty had settlements in east Kowloon, little archaeological evidence had been found until recent years.
The first archaeological study was near Sacred Hill - a slope in the Ma Tau Wai area levelled by the Japanese army in the 1940s. From 1918 to 1937, Walter Schofield, a colonial civil servant and amateur archaeologist, found remains from pre-Han (before 206BC) periods and Tang (618-907AD) and Song dynasties, according to a report by Dr Liu.
The MTR excavation is the fifth archaeological survey in Kai Tak since 2002.
But the history of Hong Kong in the Song era is far richer than just the story of the two young emperors.
By the 4th century, eastern Kowloon was a salt production hub. When the dynasty nationalised salt production, the government set up a local headquarters of the Imperial Salt Monopoly in Kowloon, spanning an area that includes today's Kowloon City, Kowloon Bay, To Kwa Wan, Kwun Tong and Tsim Sha Tsui, according to the Kwun Tong district council and studies by historians.
As Kowloon Bay became a popular shelter for ships sailing between Guangdong and Fujian during the Song dynasty, people arriving from other parts of China started to settle in the area and establish villages. Among the migrants of the time was the Lin clan from Fujian, who set up a village called Po Kong Tsuen near the present San Po Kong.
Another trace of the Song empire is the Hau Wong Temple in Kowloon City. Built in the 18th century, it is a grade-one historic building. Some people say the temple was built to commemorate Yeung Leung-chit, a military general and uncle of Emperor Shi who took him to Kowloon. But this claim is still debated.
After the Mongols routed the Song regime, succeeding dynasties kept a foothold in Kowloon, including the Ming and the Qing. Facing threats from Western military powers in the 19th century, the Qing empire built the Kowloon Fort and the Kowloon Walled City. The Walled City, which became a lawless and dirty slum, was razed 20 years ago.
Official recognition of Song-era Chinese heritage in Kowloon City did not come until British colonial rule. According to Legislative Council records, the decision was partly a political move to provide what was then a brand new colony with a "respectable halo of antiquity" and partly a strategy to preserve some open space in Kowloon for the public.
The colonial government attempted to sell the land for development in 1915. The Sung Wong Toi boulder - slated to be razed - was saved only after building contractor Li Sui-kum revealed the plan to the public and two University of Hong Kong academics petitioned for its conservation.
Some hope the new Kowloon discoveries will trigger renewed interest in Hong Kong's imperial past. "In the 19th century, people started to pay attention to the roots of Hong Kong as they looked for something which could strengthen their cultural identity," says Professor Chiu. "Later in the 1950s, a group of scholars became very keen on reconstructing the history of Kowloon and conducted a lot of studies. Yet there was very little information available from archaeological finds."