The question as to how best to dispose of this 1st A.C. was an extremely delicate one. The numerical weakness of the Cavalry Corps, holding the Wytschate and Messines line, suggested strongly that it would be of the greatest use in that area. On the other hand was the very grave danger of the Allies' left flank being turned by the sudden advance of fresh German forces north and east of Ypres, of sufficient strength to break through the very thin line guarding that quarter. In this dilemma, the C. in C., with consummate judgment, decided to send Sir Douglas Haig's Army Corps to the northern side of Ypres. The wisdom of this step became apparent on the very next day, that is on the day when the 22nd Brigade advanced to the Roulers-Menin road, and were forced back by the unexpected appearance of two Army Corps whose presence was unknown to our air-scouts. These fresh German forces as we have seen, pursued the 22nd Brigade as far as Zonnebeke, and there attacked our line with the utmost determination on the 20th and 21st. On the first of these two days, the brigade, as already described, managed to hold its own--though at great sacrifice--but the German attacking force was all the time being augmented, while our defensive force, owing to continuous losses, was getting weaker; and it is hardly conceivable that the enemy's advance could have been checked for another twenty-four hours, except for the timely arrival of the 1st A.C. As soon as the destination of this corps had been decided on between the C. in C. and Sir Douglas Haig, the latter hurried forward the Guards' Brigade to the assistance of the 7th Division, and these--as has already been explained--came up into line on the left of the R. Welsh Fusiliers on the night of the 20th, and were unquestionably very largely instrumental in preventing something in the nature of a _débâcle_ on the 21st.