Sadly, nowadays the subject of "shackles" used as devices of human restraint and oppression in many cultures, seems to be of a common occurrence.  Yet the history of this device started innocently in pastoral cultures as a means for the herdsman to fasten a beast, lest it wander around.  Today, there is not a day that passes by in the news, where the reader does not come across the term "shackles" applied to various situations.  Like that of throwing off the "shackle" of tyranny,  based upon an inner freedom which makes possible the relinquishing of outer shackles and chains that oppress us. 

Below is an investigation of this mysterious term leading to a riddle for you to solve:

All linguists are in agreement that the original meaning of the term "shackle"  appears to be of "something to fasten or attach". Beyond that point all tracks seem to have gone cold. Hence, the English Oxford Dictionary, despite numerous failed attempts, has classified the term as: of doubtful and unknown origin. 

The term first appeared around the year 1000 CE in the work of the Anglo-Saxon King Ælfric. Unfortunately information about Ælfric's life is scarce and can often only be guessed at. 

No published biography exists (such as Asser's Life of King Alfred for the earlier king of Wessex) and therefore what little information we have has to be drawn from references in his own writings, and our knowledge of the historical events towards the end of the tenth century. Accepted dating, however, places his birth c.950 and his death c.1010.

Since Ælfric was the most prolific known writer from the Old English period, it was vital to etymologists to search among his sources. It is well known that Ælfric was a keen student of Biblical writings, a fact attested to, by his often use of the wealth of classical and biblical allusions in his writings. 

Unfortunately, no where is the term "shackle" to be found in the Hebrew/Aramaic Old Testament text, nor in the New Testament written in the Greek language. In Hebrew/Aramaic, the terms for ''shackle" are Ziyqah, Kebel, and Nekhosheth (In Arabic, a sister language, their cognates would respectively be: Diyq, Kabbal, and Nahhas). While in Greek, the term for "shackle" is Pede.
 
 

It was over half a century down the road that the term "shackle"  was reintroduced in the English language, and popularized in Shakespeare's play : All's Well That Ends Well, when the king said in Act 2, Scene 3:
 

Lately, to the bewilderment of etymologists, through Forensic Linguistics, a discipline adjunct to the Science of Archeology, the source of the term was discovered in Old and Classical Arabic. 

Can you guess what is this mysterious source of the term "shackle" in the Arabic language?

CLUES: 

Today in the Modern Arabic language the term for "hinge"  is all of what has been retained from the original term although in a nasalized form.  Incidentally the Arabic term for "entangled and dubious problem" is also a direct derivative of this original term.

Remember, the old Arabic saying "You can hide the truth in the Eye of the Sun".  As truth disappears in a blinding light. Nothing appears but the Sun Burned Bright. Only the squinting will pierce the vale of illusion of this sunlight, therein lies your answer.