MacNeill finds supporting evidence for Sliab Lecga being the old name for Montpelier Hill in the poem ‘Bend Etair II’ contained in the The Metrical Dindshenchas.  According to MacNeill, Bend Etair II;

‘purports to explain the names of Étar (the Howth Peninsula) and four places of note which are visible along with Étar and perhaps from it – Dún Brea, Oe Cualann, Druim Ing, and Sliab Lecga.  Dún Brea is at the sea and a river-mouth, and its name beyond doubt is preserved in that of Bray.  Sliab Lecga… is close to Bruiden Da Derga.  That the names are given in topographical order appears from the phrase “Sliab Lecga in lathair iar sain” – [Slieve Lecga is the next place] following the mention of Druim Ing.  If I am right in identifying Oe Chulann with Two Rock and Three Rock Mountains, Druim Ing should be Kilmashogue Mountain, between these and Sliab Lecga as viewed from the north…’ (7).

The translated text of the poem regarding Sliab Lecga reads:

“Mount Lecga, the next spot prepared against ruses and pillage, is the fifth bright “knot of testing,” (8).

If Sliab Lecga really is Montpelier Hill, then the line ‘prepared against ruses and pillage’ is certainly enticing as it may hint at a defensive features on the site.  This could be the large enclosure monument on the slopes (DU025-020002) or perhaps a reference to a large hillfort that lies as yet unidentified, hidden by the modern forestry plantation or obliterated by the creation of the deerpark in the eighteenth century.