The state’s highest court needs an informant.
A portrait of an unnamed justice hangs outside the chambers of state Supreme Judicial Court Chief Justice Ralph D. Gants, and officials are seeking the public’s help in identifying the mystery jurist, who probably served on the SJC during the late 18th or early 19th century.
Gants is offering perks to the person who comes forward with reliable information.
“If you know the identity of this Justice, and provide the SJC with reliable authentication, you will be invited to the John Adams Courthouse to stand with Chief Justice Ralph D. Gants as he places a plaque identifying the Justice to the frame surrounding the painting,” the SJC said in a statement.
The downtown courthouse, completed in 1894 at a cost of approximately $3.8 million, houses the SJC, the Massachusetts Appeals Court, and the Social Law Library, which is the nation’s oldest law library, according to the state Trial Court website.
The SJC and Social Law Library moved next door in 1939 but returned to the august courthouse in 2005 after a massive renovation, the website says.
The statement said the justice in question may have served on the SJC between 1780 and 1820. The portrait depicts a middle-aged man with short brown hair, clad in formal attire and wearing a solemn expression. His eyes appear to be green.
In addition to the VIP treatment during the plaque ceremony, the lucky tipster will get an up-close look at the breathtaking venue where the state’s highest court hears cases, according to the release.
“Following the identification ceremony, you will be given a guided tour of the beautifully restored John Adams Courthouse,” the statement said.
Founded in 1692 as the Superior Court of Judicature, the SJC is believed to be the oldest appellate court in continuous existence in the Western Hemisphere.
Jennifer Donahue, an SJC spokeswoman, said Gants came up with the idea to solicit tips in an effort to learn the identity of the justice. But officials have been trying to crack the case for more than a decade.
“Efforts have been made periodically within the SJC to identify the subject of the portrait from at least 2005 when we were re-hanging all the portraits in the John Adams Courthouse,” Donahue wrote in an e-mail.
The identity of the artist also remains a mystery.
Donahue said in a follow-up interview that portraits are periodically loaned or gifted to the SJC. One of the primary lenders is the Social Law Library, whose pictures on loan to the court include a portrait of Oliver Wendell Holmes Jr. Holmes served as chief justice of the SJC from 1899 to 1902 and later sat on the US Supreme Court.
Also, Donahue said, some retired state chief justices have commissioned their portraits and donated the finished products to the court.
Among the retired chief justices who’ve had their portraits unveiled in recent years are Margaret H.Marshall and Roderick L. Ireland.
Robert J. Allison, a history professor at Suffolk University who specializes in the early American republic, said identifying dignitaries from the 17th and 18th centuries can be difficult.
“I hate to say it, but a lot of these guys do look alike,” said Allison, whose books include “The Boston Tea Party,” “The Boston Massacre,” and “A Short History of Boston.”
Case in point: a statue of George Washington at the State House that was thought for most of the 19th century to depict Samuel Adams.
“People will get them mixed up,” Allison said. “Memory fades. . . . It’s a great mystery. I’m glad that after all these years, Justice Gants said, ‘Who is this?’ ”
As for the identity of the artist, a spokeswoman for the Museum of Fine Arts in Boston said the museum couldn’t offer anything conclusive based solely on an image. But one candidate could be Chester Harding, a portrait artist who painted local officials during the period in question.
Harding was born in 1792 in Conway and spent six months in the Hub in 1823, where he “received an astounding reception and more commissions than he could carry out,” according to the National Gallery of Art website.
He later moved to Northampton before settling in Springfield in 1830, the website says, and he’s believed to have painted more than 1,000 portraits. Does that include the one hanging outside Gants’s chambers? The jury’s still out.Emily Sweeney of the Globe Staff contributed to this report. Travis Andersen can be reached email@example.com. Follow him on Twitter@TAGlobe.