– With the Islamic State in Iraq and the Levant on the doorstep of his hometown in eastern Syria, Yaroob al-Abdullah had little time. He had rushed his wife and four daughters to safety. Now he had to save the thousands of ancient artifacts he loved.

In a week of furious work in summer heat, tired and dehydrated from the Ramadan fast, the head of antiquities in Deir el-Zour Province and his staff packed up most of the contents of the museum in the provincial capital. Then he flew with 12 boxes of relics to Damascus.

The pieces included masterpieces: A nearly 5,000-year-old statuette of a smiling worshiper. A mural fragment from a 2nd-century temple for the god Bel. Thousands of fragile clay tablets inscribed with cuneiform writing that provide a glimpse at life nearly 4,000 years ago in the Semitic kingdom of Mari.

The move was part of a mission by antiquities officials across Syria to evacuate everything that could be saved from ISIL and looters. The extent of the 2014 operation has been little known until now, but its participants described a massive effort — at least 29 of Syria’s 34 museums largely emptied out and more than 300,000 artifacts brought to the capital.

The pieces are now hidden in secret locations known only to the few specialists who handled them, said Maamoun Abdulkarim, who as head of the Directorate General of Antiquities and Museums in Damascus oversaw the operation. “Other than that, no one knows where these antiquities are — not a politician, not any other Syrian.”

There’s much that couldn’t be saved. The damage is most symbolized by Palmyra, the jewel of Syrian archaeology. ISIL captured it last year and proceeded to blow up at least two of its most stunning Roman-era temples. Syrian government forces recently recaptured Palmyra from the militants and discovered they had trashed the city museum, smashing statues and looting relics — though fortunately about 400 pieces had been hidden before the ISIL takeover.

Wherever ISIL overran territory in Syria and Iraq, ISIL jihadis relentlessly blew up, bulldozed or otherwise tore down monuments they consider pagan affronts. They and other traffickers have also looted sites and sold off artifacts. Even in the museums that were evacuated, some items were too large to move — giant statues or ancient gates and murals — and fell into ISIL’s hands.

But the 2,500 archaeologists, specialists, curators and engineers with Syria’s antiquities department, including some who defected to join the opposition, have often risked death to protect what they can.

One 25-year-old woman led a military convoy carrying antiquities out of the northern city of Aleppo, a major battleground between rebels and government forces. Out of fear for her safety, she requested anonymity.

Guards at archaeological digs and other sites in areas now under ISIL control secretly keep tabs on the ruins and feed Abdulkarim photo updates on WhatsApp. Several of them have been killed. Khaled al-Asaad, 82, Palmyra’s retired antiquities chief, was beheaded by the extremists in August after spiriting away artifacts from the city’s museum and refusing to reveal the location to ISIL militants.

Ziad al-Nouiji, who took over from al-Abdullah as head of antiquities in Deir el-Zour, knows the danger: ISIL militants besieging the area are hunting for him, posting his name on their Facebook pages as a wanted man. He relocated his family abroad but is staying put. “This is my duty, my country’s right. If we all left the country and our duties, who would be left?” he asked.

The antiquities authorities didn’t take any chances, even clearing museums in government-controlled areas. At the National Museum in Damascus, the halls and galleries have been empty since the artifacts were hidden away.

“The heroes here are the Syrian men and women on both sides who … are willing to risk their lives for their heritage,” said former antiquities directorate chief Amr al-Azm, who now teaches at Shawnee State University in Ohio. “That’s what gives me hope for the future of Syria.”

A vital crossroads throughout history, Syria holds a legacy from multiple civilizations that traded, invaded and built cities across its territory — the Akkadians, Babylonians and Assyrians of ancient Mesopotamia, various Semitic kingdoms, the Romans and Byzantines, and then centuries of Islamic dynasties. The country is dotted with “tells,” hills that conceal millennia-old towns and cities, some of which have been partly excavated and many more that are still waiting to be discovered.

“People who worked in digging know what it is like to look for a certain piece and then to find it,” said Al-Abdullah, now the head of the Damascus museum. “We consider this piece as one of our own children. As we fear for our children and family, we fear for those antiquities.”