<prompt> Translate the following text to EnglishKwenye mwisho wa mashariki wa majumba ya maonyesho, nguzo mbili ndogo na mduara wa marumaru ya kijani huashiria mahali ambapo malkia alikaa wakati wa huduma; kwenye sakafu ya nave chini, mduara wa mawe ya rangi upande wa kulia wa katikati ni Opus Alexandrinum, mahali ambapo maliki wa Byzantium walipewa taji.  <response>: At the east end of the galleries, two small columns and a circle of green marble mark the spot where the empress sat during services; on the floor of the nave below, a circle of coloured stone to the right of centre is the Opus Alexandrinum, the place where the Byzantine emperors were crowned. 