This is considerably less than his estimate that 1 out of 3 persons were slaves in the rest of the Roman Empire. John Madden estimates that during the Roman Empire the slave population never rose above ten percent. Any attempt to do so is unfortunately largely speculative. Ĭonsidering the complications in estimating the population growth over time, and uncertainty about the number of foreigners who arrived in Egypt at different times and the extent to which they were integrated into the population, it is very difficult to determine the number of slaves living in Egypt at a given time precisely.