The new BBC documentary series Civilisations asks what value we should place on the relics of the past. For one archaeologist, who is given a moving tribute in tonight’s episode, defending them was a matter of life and death.

Khaled al-Asaad was born and died in Palmyra, a Unesco world heritage site that ranks alongside Pompeii for its beauty and importance. For half a century, he was the ancient Syrian city’s most dedicated guardian – until he was beheaded by Isil militants in 2015.

After his death, unverified images were circulated of a dismembered corpse, supposedly his, hanging from a traffic light in the surrounding modern town of Tadmor. But according to other sources – including his colleague Maamoun Abdulkarim – Asaad’s body was found tied to one of the ancient pillars in the ruins of Palmyra’s central square.

For a man who devoted his life to recording the past, parts of Asaad’s own history remain sadly obscure. His age, at the time of his death, was variously reported as 81, 82 or 83. Born in the early Thirties, as a boy he went to boarding school in Damascus, hitching rides with lorry-drivers at the start of every term. He studied history at university there, and learnt the ancient language of Aramaic (his later fluency was considered a rare achievement – few Syrian scholars mastered the language). He returned to Palmyra in 1963, and for the next 40 years worked as the director of its museum. Even after stepping down in 2003, he stayed on as a staff expert.