In 2007 the town of Chilmark, the Martha’s Vineyard Land Bank and the Howard Hillman family announced a three-way land swap that was designed to save a historic house, open up a new conservation corridor and create more affordable housing up-Island.

Six years later, the plan remains in limbo. A three-day trial in Dukes County superior court was held this week to determine whether the agreement is still valid.

The case is actually rooted in events that date back a decade ago when the home of the late Burton Engley — a historic home off Middle Road in Chilmark and the 10th oldest house in Chilmark — was purchased by the town and the land bank in a joint $1.2 million deal. The original plan called for converting the Engley home into an affordable year-round residence, with the land bank holding a conservation restriction on the surrounding property. That later turned into a far more complicated deal that called for the Howard Hillman family to take ownership of the Engley home and donate land for four affordable housing lots.

Two years after the deal was struck in 2007, the Hillman family said they were backing off of the deal because so much time had gone by with no completion.

“We’re going to ask you to enforce this,” Chilmark town attorney Ronald H. Rappaport told the Hon. Gary A. Nickerson in opening statements Monday. “We’re not in the development business and there is a public purpose here.”

But Jennifer Roberts, the attorney representing the Hillman family, claimed that because the town dragged its heels for so long, the deal became what she called a “dead letter.” Noting that a conservation restriction change that was part of the deal has still not been signed off on by the state Secretary of Environmental Affairs, Ms. Roberts concluded: “There is no obligation on the part of the Hillmans to perform.”

The history of the land deal was recounted by both attorneys in their statements Monday in the Edgartown town hall where the trial is being held. It was a complicated three-way agreement among the Hillmans, Chilmark and the land bank. The Hillman family owns more than 100 acres around the Engley property and the land bank held a trail easement across the middle of that property. The swap called for the land bank to give up the easement in exchange for another trail easement on the border between the Hillman property and a Sheriff’s Meadow property. It would have created a broad trail network linking South Road to the Middle Road area and Waskoskim’s Rock Reservation on North Road.

As part of the agreement, the Hillman family agreed to donate 10 acres near South Road to the town of Chilmark; six of the 10 acres would be owned by the land bank and the middle of the parcel would be turned into four one-acre affordable housing sites, owned by the town. In exchange, the Hillmans would be granted ownership of the Burton Engley house.

In 2007, Chilmark voters authorized selectmen to execute the deal, and the state legislature created an act authorizing the swap in 2008.

In court Monday, points of contention were clear. Mr. Rappaport said the town proceeded in good faith but that the deal was complicated and involved many moving parts, including the state legislature. “We couldn’t predict how long it would take for the legislature to act,” Mr. Rappaport said.

Ms. Roberts pointed to the length of time it took to complete the transaction and to poor communication from the town. “[After the agreement was signed in October 2007] it went into a black hole,” she said. “The Hillmans heard nothing and were not asked to participate in any way.” Further, she said, the conservation restriction still does not have final approval.

There was no closing date on the original 2007 agreement. Both sides agreed Monday that the law states that if an agreement does not stipulate that time is of the essence, then the closing must take place in a reasonable amount of time.

If the agreement is not enforced, the town will remain as steward of the Burton Engley house, which has now fallen into serious disrepair.

Witnesses at trial included Frank Fenner, a Chilmark selectman, Irene Del Bono, who works for the state Secretary of Environmental Affairs, and James Lengyel, executive director of the land bank. The land bank was represented at trial by Diane Tillotson, an attorney with Hemenway & Barnes in Boston. Howard Hillman was present in the makeshift courtroom.

The trial finished Wednesday and is now in the hands of Judge Nickerson for a decision.