An old painting shows that Henry VII's palace had a chapel at its eastern end, but it was never clear exactly where it lay.
"The perspective of the painting leaves a bit to be desired," Bowsher said.
Until now archaeologists had assumed that the chapel was destroyed with the rest of Placentia.
All that changed three weeks ago, when Bowsher was called in by the Greenwich Foundation to monitor building work being done at the college.
At the site Bowsher spotted a brick peeking out from a muddy hole in the parking lot.
After further excavation revealed the discovery, it caused excitement in the British archaeological community.
"This is the most significant find from Greenwich over the last ten years," Bowsher said.
Records show that the chapel was a focal point for a number of important royal events.
"Henry VIII attended St. George's Day services [in honor of England's patron saint] at the chapel, and it is thought that two of his marriages took place in a closet overlooking the chapel," said Duncan Wilson, chief executive of the Old Royal Naval College, as the complex is now called.
Beyond the chapel, archaeologists have also uncovered the vestrya room where religious objects were keptand the old river frontage, where Tudor monarchs may once have strolled.
"We uncovered a Tudor wall and a cobbled waterfront walk used before the river was pushed further back in the 18th century," Wilson said.
Now Bowsher and his team are busy finishing the excavations before burying the chapel again.
"Everything is being photographed and recorded before being back-built under protective layers," he said. "We couldn't leave it uncovered, as it would just disintegrate."
The glass and stonework is being carefully wrapped and sent off to a laboratory for analysis, he added.
"We won't know the full story until a few weeks after the analysis is done," Bowsher said.
Eventually the finds will be put on display at the visitor center at the Old Royal Naval College.
Free Email News Updates
Sign up for our Inside National Geographic newsletter. Every two weeks we'll send you our top stories and pictures (see sample).
SOURCES AND RELATED WEB SITES