  By systematic investigations of the magnetic, transport and thermodynamic
properties of single crystals of EuFe2(As1-xPx)2 we explore the complex
interplay of superconductivity and Eu2+ magnetism. Below 30K, two magnetic
transitions are observed for all P substituted crystals suggesting a revision
of the phase diagram. In addition to the canted A-type antiferromagnetic order
of Eu2+ at approximately 20K, a spin glass transition is discovered at lower
temperatures. Most remarkably, the reentrant spin glass state of
EuFe2(As1-xPx)2 coexists with superconductivity around x = 0.2.
