Complex sentence: Two years earlier the works had been sold for 1,500 livres to Louis de Ridouet-Sancé, who probably invested about 9,000 livres but failed to make the business profitable.
Split into simpler sentences: Two years earlier the works had been sold for 1,500 livres to Louis de Ridouet-Sancé. He had probably invested about 9,000 livres but had failed to make the business profitable.