The correspondence began again, but two years later. In this correspondence, Elisabeth and Descartes discuss an illness Elisabeth suffered from in the summer of 1645. Descartes writes to Elisabeth that he thinks her symptoms are caused by sadness. This could very well have been true, as Elisabeth's brother Philip had challenged a family suitor and then stabbed the suitor in public, resulting in social backlash. This caused Elisabeth much distress and worry. Elisabeth originally intended the letters to be private and has no extant philosophical works. This makes her place in the history of philosophy complex and the subject of debate. This specific correspondence between Elisabeth and Descartes is often ignored by many historians, as they see it as insignificant, but a few regard it as influential in that Descartes and Elisabeth seem to be talking of the "passions of the soul", as Descartes referred to them. Some historians have remarked that Elisabeth could have been a philosopher in her own right if it had not been for a lack of a systematic presentation of her philosophical position.