Complex sentence: The "Economic and Philosophical Manuscripts of 1844" had been written between April and August 1844 still Marx recognized that the "Manuscripts" had been influenced by some inconsistent ideas of Ludwig Feuerbach.
Split into simpler sentences: The "Economic and Philosophical Manuscripts of 1844" had been written between April and August 1844. Soon, though, Marx recognized that the "Manuscripts" had been influenced by some inconsistent ideas of Ludwig Feuerbach.