Complex sentence: The severed feet were heaped in two piles with those of his favorite concubine, whose feet were unusually small, placed on top, and these two piles of feet were then doused in oil and set alight to be what he called "heavenly candles".
Split into simpler sentences: The severed feet were heaped in two piles with those of his favorite concubine, whose feet were unusually small, placed on top. These two piles of feet were then doused in oil and set alight to become what he called "heavenly candles".