Complex sentence: Despite his record of defeats, he was able to retain his position, he was able to attain command ahead of the more popular Marshal Browne because of the support of his brother who had significant influence over military appointments.
Split into simpler sentences: Despite his record of defeats, he was able to retain his position. He was able to attain command ahead of the more popular Marshal Browne because of the support of his brother who had significant influence over military appointments.