Numbers 243. Report of Colonel Leopold von Gilsa, Forty-first New York Infantry, commanding First Brigade.

HDQRS. FIRST Brigadier, FIRST DIV., ELEVENTH A. C.,
May 10, 1863.

GENERAL: I have the honor to submit to you the following report of the battle at Chancellorsville, as far as the First Brigade of the First Division did take part in the engagement:

The First Brigade had the following position: Two regiments in line of battle along the road from Chancellorsville to Gordonsville, front toward the Plank road, connecting on the left with the Second Brigade, First Division, and two regiments in a right angle to the above line, also in line of battle. The whole brigade was about 1,400 men strong, and I foresaw, having no reserve at all, that I would be obliged to leave that position in case of an attack by strong forces of the enemy. All representations stated to the division commander to send me reserves were unfruitful, except that the Seventy-fifth Ohio was located near my left wing. This was in part division reserve. The cavalry returned from the front of my line, and reported no enemy at all in front. A quarter of an hour later, a patrol of the Forty-fifth New York Regiment reported masses of the enemy in an open field opposite my line. I reported this fact at once to the division commander, and at the same moment my skirmishers were driven in by overwhelming forces of the enemy. The whole line was at once engaged furiously, and my brigade stood coolly and bravely, fired three times, and stood still after they had outflanked me already on my right.

The enemy attacked now from the front and rear, and then, of course, my brave boys were obliged to fall back, the Fifty-fourth New York and the right wing of the One hundred and fifty-third Pennsylvania forcing their way back through the enemy's skirmishers in their rear. I had no regiment to cover my right flank, and no reserves to drive back the enemy with the bayonet. Retreating, I expected surely to rally my brigade behind our second line, formed by the Third Division, but I did not find the second line; it was abandoned before we reached it.

I am obliged to express my thanks to the men of my brigade, with very few exceptions, for the bravery and coolness which they have shown in repulsing three attacks, and they retreated only after being attacked in front and from the rear at the same time; but I am also compelled to blame most of my line officers that they did not or could not rally their companies half a mile or a mile more back, no matter if it could be done under the protection of a second line, and I hope that in the next engagement every officer and man of may brigade will try to redeem this unsoldierlike conduct. On the same evening, nearly the whole brigade was rallied near General Hooker's headquarters, and was ordered to protect three batteries.

I regret to report to you, general, a very great loss of killed and wounded, officers and men, but naturally the loss of my brigade is exceedingly large, the attack by the enemy having been as strong and furious as I never have seen before.

I have the honor to be, general, very respectfully, your most obedient servant,

LEOPOLD VON GILSA,

Commanding First Brigade.

Major General O. O. HOWARD, Commanding Eleventh Army Corps.