qnli question: How long did he spend in the desert? sentence: Athanasius, after remaining some days in the neighbourhood of the city, finally withdrew into the desert of Upper Egypt, where he remained for a period of six years, living the life of the monks, devoting himself to the composition of a group of writings; "Apology to Constantius", the "Apology for his Flight", the "Letter to the Monks", and the "History of the Arians".