Henry I was interred in front of the high altar of Reading Abbey (shown here) after he died in 1135, according to official histories of the British monarchy.

If the English King Richard III was the "king in a car park," King Henry I may prove to be the "king in a playground."

In the wake of an archaeological dig that found the bones of Richard III beneath a parking lot in Leicester, England, British historians and archaeologists are turning to a church and school yard in the town of Reading in search of the remains of Henry I, who ruled England from 1100 to 1135. The modern buildings are on the site of the old Reading Abbey, which was shut down — its abbot was hanged for treason — in 1539.

"We have a very good idea, within a few feet or yards, of where Henry was buried," said John Mullaney, a local historian and author of "Reading's Abbey Quarter: An Illustrated History" (Scallop Shell Press, 2014). Mullaney and other local leaders have been joined in their efforts with Philippa Langley of the Richard III Society, the screenwriter who spearheaded the search for that lost king. [In Photos: Search for the Grave of King Richard III]

Whether Henry's bones remain where they were laid to rest is a mystery, Mullaney said. But even if archaeologists can't find the body of the king, exploration of the ruins could answer unsolved questions about abbey life and what the site was used for before Henry I ordered the abbey built.

Henry's abbey

Henry I was the fourth son of William the Conqueror, who, upon his death, granted the throne to his oldest son, William II. William the Conqueror's second son, Richard, died before his father, and the third, Robert, got the throne of Normandy. Henry was left to purchase a bit of western Normandy from his brother. After a bout of familial infighting and the death of William II in 1100, Henry seized the throne of England. In 1106, he conquered Normandy and kept his brother Robert in captivity until Robert's death 28 years later. [Family Ties: 8 Truly Dysfunctional Royal Families]

According to the official histories of the British monarchy, Henry I centralized administration and tax collection in England. In 1121, he founded an enormous abbey in Reading. He was interred in front of the Reading Abbey's high alter after his death in 1135 — rumored to be the result of eating too many lampreys (a type of eel).

Over the centuries, Reading Abbey became one of the wealthiest abbeys in England. By 1539, the abbey's income was 2,000 pounds a year, putting it in the top dozen richest religious houses in the country, Mullaney told Live Science.

During the reign of the Tudor king Henry VIII, however, religious houses came under attack by church reformers who decried them as corrupt. In 1531, Henry VIII declared himself Supreme Head of the Church of England — part of his efforts to get a divorce from the first of his six wives. This designation gave him a great deal of power to shut down monasteries and seize their assets for the crown.

Reading Abbey was one of the victims, as was its last abbot, Hugh Faringdon (or Cook). Faringdon stood firm against Henry VIII's efforts to shut down the abbey and was convicted of treason for his efforts. He was condemned to hanging, drawing and quartering — that "delightful way of disposing of people," Mullaney said.

Fortunately for Faringdon, his executioner either took mercy on him or messed up. Faringdon died during the hanging at the gates of his abbey, spared the torture of disembowelment and dismemberment. [Medieval Torture's 10 Biggest Myths]

An abbey's ruins

After that, much of the abbey fell into ruins and was stripped of its valuable lead and stone. During the English Civil War of 1642 to 1651, ramparts were built right through the old cloisters and nave of the church. In the past few years, Mullaney said, the ruins have become so unstable that they've been closed to the public.

The main goal now, Mullaney said, is to shore up the ruins and reopen them to the public. The group hopes to get a grant from the U.K's Heritage Lottery Fund to this end, and is seeking matching funds.

"They're going to grant us, we hope — and it looks very hopeful — just under 2 million pounds [about $3 million]," Mullaney said.

A second effort, called the Hidden Abbey Project, aims to secure funding for a ground penetrating radar (GPR) survey of the ruins. GPR uses radar to create images of the subsurface, revealing buried objects that might be of archaeological interest.

Some parts of the abbey still stand, including its old dormitory, portions of the refectory and south and north transepts (wings of a church), the chapter house and portions of the Hospitium, where pilgrims to the abbey would have stayed. But much of the abbey's west side is gone, and no one knows what lies under the chapter house. There could be a cellar, Mullaney said, or possibly some human burials. The abbey site was also in use for many years before the abbey was built; Danish forces may have even used the high ground there as an encampment in the 800s.

A GPR survey also might reveal what happened to Henry I's remains.

"We know there was quite an ornate tomb, a monumental tomb, probably with his effigy over the site," Mullaney said. As late as the reign of Richard II from 1367 to 1400, this tomb still existed.

Now, the area that used to be the church's high alter is land owned by a defunct prison, and a school and playground sit over the site where Henry I's tomb would have been, Mullaney said.

In the late 1700s and early 1800s, diggers uncovered three sarcophagi, one of which was made quite well, at the site. It could have been Henry I's, Mullaney said, but no one knows. All three sarcophagi went missing.

Another set of rumors dating from the 1700s holds that looters went looking for Henry I's coffin during the reign of Edward VI, between 1547 and 1553. (Edward VI was the son of Henry VIII and his third wife, Jane Seymour.) According to those tales, the looters found Henry I's coffin but were disappointed that it was not made of silver as they'd thought; then, they scattered the bones and left.

Or, Henry's grave might be undisturbed, Mullaney said. Either way, there's some chance that the monarch could be recovered. Right now, he's the only English monarch since 1066 whose grave is still lost.

"If these bones were scattered around the place and you could gather them together, then we may be able to say, 'Well, this is Henry,'" Mullaney said. "And we could maybe reinter him with the dignity that one associates with any person, let alone a royal person."

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