The Two hundred Posts, or The Battle for Middlelothian.
To set the scene..............

It is the end of the second age, and ill tidings reach noble, if hairy, ears. Mayhap there is something rotten in the staves of Lothian.  Now read on.

   The third millennium, half a decade started, but scarce dry behind the years, brought wandering Night Wights and 'orrible Orks, who left signs that only skilled eyes could read. 
    Strange tribes* with and sometimes in, unpleasant habits, now roamed abroad, and more importantly near home. Read on brave reader if you dare, keeping your wits about you.
    In Fortress Cramond the mighty Chiefs of SWT, Guardians of the twig and the bird on it, did look to the safety of their lands, where the bones of brave hero Hermand are said to rest in peaceful triumph.  The Chief's concern further raised by tales of weevil deeds and iffy weather lurking hard by the borders of our blood bought Birchwood.  After much discourse and some muttering, the Lords acted, sending forth Alan, son of Ander,  a rider of the mountainous northern ranges out, far into the byways of the Shire.  His task, as he accepted it, to find report of the state of post and wire.  Twenty leagues or less beyond the Fortress, Lord Alan, who some will insist on calling Strider, did find plainly rotten staves and rust where once brave new wood and steel had stood but two score of years before.
  Swiftly turning to drive his mount, fleet Astra, fast homeward he knew his cunning eye and skilful ear had whispered true of danger, and mixed metaphor, hid hiding in the bosky dells, closer by the fortress Cramond than any had dared think. In that very fastness did Alan then set to scribing in ink and triplicate a report of deep foreboding.
     Upon receipt, and wasting little time, the Chiefs did set a plan to defend the Darkling Wood from Strange Tribes and wooly-minded cloven-footed beasts of endless appetite** and within the shadows of the fortress, mindful of the cost, there was made a cunning budget wrought to re-forge those failing fences.  Before the work could start, King Stephen knew the perimeter of Hermand's Foil must be charted, to guide the humble working folk whose task, or post it was to raise up this shield of first defence.  For this exacting task a great wizard was sought, near lost in the mists of legend, one of whom the ancient sagas spoke, having time, wit, boots and cunning equal to the task. One whom legend told, could talk with Ents, and was almost as old.  The Chiefs mustered great magic to scry the runes, sent out search parties and looked under the larger stones. After much travail Grey Owl, for 'twas he they searched, was found, cleaned, summoned, and appraised.
Thus the second epic task began ........   right shortly after lunch. 
With pencil sharp and notebook small The Owlet, for so he is appelled by common folk, set out alone and, by himself, reached Hermand, where he faded from sight by means of a special cloak made by the elven folk in far Barbourian lands.
Invisible to prying eyes, slipping swift and silent as a silken shadow, he measured, and surveyed, in a single day the borders of the sacred land East, South, and West.  The North we know he wisely left untrammelled, since that border was safe in the guardianship of Lothian Roads Department and held safe by Brave Lothian Volunteers, and anyway it was getting a bit dark by then. 
Many tales have been told how, unobserved, and unheard, that Mage did ford ditch, leap hedge and duck bough, leaving not a trace, save the odd skid mark.  Sadly those tales are long lost in the mists of time, they might yet be rediscovered but we wouldn't want to build the part up.  The reader must judge them for himself, the Owl being too modest to speak of the struggle, and his memory a bit suspect at best.
With eagle eye, and a good guess where gloom or boggy bit parried sight, the reckoning was made.  His fabled magic safety boots, gifted to him by SWT (Swift Wizard Transport) had kept him steady and dry of foot around the circumference of Hermand's Land, a distance that would have wearied and dampened a lesser or shorter booted mortal. 
After much deliberation, and some crossing out, the measured runes he counted up and swiftly scribed them down across the page, the art of joined up writing no daunting task for he, having been to special schools.  Then, with no ceremony but a small cloud of blue smoke, Grey Owl vanished from the now shadowed park. Humble peasantry would call it magic, others a Land Rover.  Either way, that Mage did hurry to his stronghold at Tower Braxx, which is called Tarbrax in the Elfish tongue. From there, in the twinkling of an eye (or perhaps two) arcane and secret devices sent the hard won intelligence to Cramond's steadfast Gate.  There, sages transcribed it from the ancient tongue of the Old Empire (that the Owl used to confuse his enemies), into that modern metered speech and mystic symbols understood by those who walk abroad, or at least as far as the Frankish lands.
So the posts were numbered,and their spacing set down, that no more would scribes scratch their heads and guess.  One more part of the great unknown was now known, the fog of ignorance pushed back and the veil of confusion rent asunder. Now came the simple task of fencing, made possible by wit, magic and surveying, arts now lost.
And did anybody thank that Mage? Only the Owl knows.

*Example.  The Distant MacDonald tribes, no longer penned away behind the Great Pond of Atlan, did desecrate great swathes of land, devouring cattle, trees, and any trace of culture they happened on. Rarely seen, they could be tracked by their fast growing middens, nothing would thrive where they had eaten.  Except Labradors. 
Their Chief Ronald "Mad Ron" MacDonald was finally slain in the land of the Franks and buried beneath a mound of polystyrene food wrappings. A single and appropriately tasteless golden M marks his grave.
** Sheep oh gormless one