Mackensen enters Bucharest on a white charger; it was his 67th birthday.
December 6 1916, Bucharest–The last-ditch efforts by the Romanians to defend their capital had ended in defeat three days earlier; it was now clear that they could no longer prevent its fall. Neither Falkenhayn nor the Romanians were interested in a battle within the city, and Falkenhayn agreed to a brief 72-hour armistice to allow the Romanians to evacuate and leave it as an open city. Both sides were busy during the interim, however; Falkenhayn and Mackensen brought up their troops and pursued the Romanians on the outskirts, while the Romanians and British destroyed as much of military value as they could.
On December 6, Mackensen entered the city at the head of his army, riding in on a white charger. In Germany, there was celebration; the Kaiser even brought out champagne (an extravagance in wartime) for the occasion. This was the great victory they had been striving for all year. Chancellor Bethmann was particularly pleased, as now he could suggest peace terms to the Allies from a position of strength.
On the same day, the last Romanian troops cut off in western Wallachia by Mackensen’s push across the Danube surrendered. Together with the men caught up in the retreat to and from Bucharest, the Romanians would lose through mid-December 147,000 PoWs, along with 73,000 killed or wounded and 93,000 missing (presumably deserters). This left them with only 70,000 troops in the field, who were hastily falling back to Moldavia with the Central Powers directly behind them.
Sources include: Keith Jeffrey, 1916; David R. Stone, The Russian Army in the Great War; Norman Stone, The Eastern Front 1914-1917; Robert B. Asprey, The German High Command at War; Randal Gray, Chronicle of the First World War.