The first Union unit to engage was one of Sedgwick's brigades, Philadelphians led by Brig. Gen. William W. Burns, but his defensive line proved inadequate to cover the two brigade front of Kershaw and Semmes. Sumner managed this part of the battle erratically, selecting regiments for combat almost at random. He sent in two of Burns's regiments, and then the 1st Minnesota Infantry from another brigade in Sedgwick's division, and finally one regiment each from two different brigades in Brig. Gen. Israel B. Richardson's division. By the time all of these units reached the front, the two sides were at rough parity—two brigades each. Although Magruder had been conservative about his attack, Sumner was even more so. Of the 26 regiments he had in his corps, only 10 were engaged at Savage's Station.