In 1140, one source referred to the ruins as the Theatrum Pompeium, whereas another referred to it as the "temple of Cneus [sic] pompeii". In 1150, Johannes de Ceca is reputed to have sold a trillium, or round structure (i.e. the theatre curve) to an ancestor of the Orsini family. In 1296, the site of the theatre was turned into a fortress by the Orsini. Later in the Middle Ages, the square of Campo de' Fiori was built and the remaining parts of the theatre were quarried to supply stone for many newer buildings which still exist in modern Rome. Today, not much remains visible of the once majestic theatre, as the vestiges of the structure have entirely been enveloped by the structures that lie between the Campo de' Fiori and Largo di Torre Argentina. The largest intact sections of the theatre are found in the Palazzo della Cancelleria, which used much of the bone-coloured travertine for its exterior from the theatre. The large red and grey columns used in its courtyard are from the porticoes of the theatre's upper covered seating; however, they were originally taken from the theatre to build the old Basilica of S. Lorenzo. And while the theatre itself is no longer discernible, the imprint of the building itself can still be detected; the structure’s semicircular form can today be traced by walking east from the Campo de' Fiori through the Palazzo Orsini Pio Righetti. The path of the Via di Grotta Pinta, near the Via dei Chiavari, also roughly follows the outline of the theatre's original stage. Deep within the recesses of basements and wine cellars of buildings located in the Campo de' Fiori, arches and fragments of the theatre's walls and foundations can still be seen. The ground plan of the Palazzo Pio also reveals that many of the supporting spokes of the theatre were re-purposed into walls for new rooms. The arches that were left after the theatre’s abandonment even led to the name of the aforementioned Santa Maria di Grotta Pinta (i.e. the "painted grotto"). Excavation and study One of the first individuals to draw the ruins of the theatre was Giovanni Battista Piranesi, who made two notable etchings depicting the theatre in the middle of the 18thcentury. The first, entitled "A Demonstration of the Current Remains of the Theatre of Pompey" (Dimonstrazione del Odierno Avanzo del Teatro di Pompeo), illustrates, from