 The last rearguard action took place at Prizren on the 27th; the defenders subsequently withdrawing down the Drin River Valley and over the Albanian frontier.Mackensen elected to not follow.Following this battle and into early 1916, over 400,000 defeated and worn-out Serbian soldiers and civilian refugees, with thousands of Austrian prisoners, retreated toward the Adriatic coast on a terrible trek across Prokletije, the Accursed Mountains, that separate Kosovo and Albania, as the snow began to fall.