Dedicated in 13 BCE, what is known as the Theater of Marcellus was based on an idea of Julius Caesar. He had just defeated and killed Pompey, who had built a grand theater, and Caesar wanted to build one even more magnificent. However, his murder ended all plans for the theater. It wasn't until 22 BCE, during the reign of Augustus, that construction began. After nine years of building, the theater was finally erected. It was named after Augustus' nephew, Marcellus, who died before construction started. The theater was true to Caesar's original conception. It was larger and more elegant than Pompey's theater. The Theater of Marcellus was approximately 50 meters high. The seating area stretched to a length of 130 meters in diameter, accommodating up to 14,000 spectators. It was completely covered in white travertine and was mostly constructed of tufa, cement, and opus reticulum brickwork. Through the centuries, a number of emperors, including Nero, Vespasian, and Alexander Severus, have made numerous restorations and repairs on the theater. In addition, it underwent various uses. In the twelfth century, the Savelli family turned it into a fortress. In spite of all of its transformations, the Theater of Marcelllus remained the biggest ever built in the Roman Empire.