This case study explored how a teacher, Mr. Smith, and his students experienced a mandated performance assessment while simultaneously preparing for an end of the year high-stakes, multiple-choice assessment. We employed qualitative research methods to examine how the teacher enacted a mandated performance assessment during a unit on Byzantium and how students described their learning and classroom experiences from the unit. Drawing on Grant's idea of ambitious teaching and learning of history and Ball's work on policy realization, analysis of these (...) data indicated that Mr. Smith interpreted and enacted a performance assessment in ways that differed from how district and state policy makers intended. Despite an assessment that the district designed to promote historical thinking skills, students learned primarily factual knowledge. (shrink)