Anonymous Folles, time of Constantine IX (ca 1042-1055) AE Follis (Bronze, 28mm, 9.17g) Constantinopolis.
Obv: Christ seated facing on square-backed throne.
Rev: IS XS / bASILE / bASIL' in three lines; above, cross between two lines; below, crescent between two lines.
Ref: Sear 1836