One of the major lines, running to the Psalter as a whole, is the theology of the poor. More than every fourth psalm is dealing with the poor or forms of poverty. The discussion about a social background or a metaphorical meaning of poverty shows the lack of knowledge about the economic and social circumstances during Achaemenid period Yehud (538-332 B.C.E.) as a formative phase of the Psalter´s redaction and compilation process. Before this background the author points out the (1) biblical, (2), archaeological and (3) numismatic evidence of Achaemenid Yehud. He concludes an escalation of socio-economic poverty, with three different stages during the Achaemenid reign. These stages find their reflection in the theology of the poor in the Psalter, where we can find dynamics as well within the five books of the Psalter, as in the Psalter as a whole. The meaning of poverty in Old Testament texts might become metaphorical, but have their roots in the economic and social backgrounds, as the author shows.