The classical rabbinical writers regarded all the cities controlled by the Levites as being cities of refuge, although they considered that asylum could only be claimed against the will of a city's inhabitants if the city was one of the six main cities of refuge. Although there the six main "cities of refuge" were named in the Bible, the Talmudic sources argued that other cities could, over time, be officially substituted for these six, to take account of changing political circumstances. The substitute cities of refuge were constrained to be only of moderate size, since, if they were too small, there could be scarcity of food, forcing the refugee to imperil himself by leaving the city to find sustenance, and, if they were too large, then it would be too easy for an avenger of blood to hide in the crowds; nevertheless, the surrounding region was required to be quite populous since that way, an attack by the avenger of blood could be more easily repelled. The altar of the Temple in Jerusalem also came to be regarded as a place of sanctuary, but only counted for the officiating priest, and even then only temporarily, as the priest ultimately had to be taken to a city of refuge; when Jerusalem was under Seleucid control, Demetrius I offered to turn the Temple into an official place of sanctuary, though the offer was turned down.