The pin harp is shown being played by maidens in the stone reliefs on the walls of the Angkor Wat temple complex.
It lends its name to pinpeat orchestras, which perform ceremonial music of the royal courts and temples in Cambodia.
Archaeology lecturer Preap Chanmara says unlike the other orchestra instruments - cymbals, xylophones, flutes and drums - the pin harp has been lost.
"We know that there are many music instruments on the sculptures - some even dating back to the time before Angkor Era: the 7th century to the 13th century," he said.
"There were many temples and sculptures back then, so there were also many different kinds of music instruments.
"Some are still being used today, whereas some others were lost."
Composer Him Sophy says the puzzle of Cambodia's missing harp had always haunted him.
"I [want] enthusiastically to know what and why it disappeared," he said.
"[On] the other side, as a composer, I love harp very much - all of my compositions I use harp, even for my symphony."
Using the carvings and other harps as a blueprint, Him Sophy joined a French researcher and musician Keo Sonan Kavei in recreating the small boat-like instrument using animal hide and silk string.
Keo Sonan Kavei says making the harp left him with "two types of happiness".
"I was worried as to whether or not it could be played," he said.
"Secondly, I was worried as to whether or not somebody before me has made it before.
The only person to play the harp so far has been Keo Sonan Kavei's 13-year-old daughter, Sereyroth.
"When she started to learn it, I could see that she was talented," he said.
"There are five generations of musicians in my family - when it was my turn, I had to rediscover something that was once lost and update it so that the world can see Cambodia's ancient music instruments.
"We're just putting it back out in the world."
With arts, music and dance almost destroyed during the Khmer Rouge regime, the effort to revive Cambodia's traditional music has been embraced by international arts bodies, culminating in the festival Season of Cambodia this month in New York.
Him Sophy says while no one knows how exactly to play the pin harp or what it should sound like, its value lies in what it represents - and the future compositions it will inspire.
"Now we not only revive music during the Khmer Rouge, we revive since the Angkor period," he said.
"For 300 years that [empire] controlled the whole of South-East Asia and now we are building our culture also, that is the pride of Cambodia and the pride of the world.
"That is the value of what we are creating."
Ellen, Rosa. 2013. “Musicians rebuild Cambodia's lost ancient harp”. Yahoo News Australia. Posted: May 21, 2013. Available online: http://au.news.yahoo.com/latest/a/-/latest/17250773/musicians-rebuild-cambodias-lost-ancient-harp/