What roman author described the technique of Opus quadratum?
Vitruvius Marcus Vitruvius Pollio (born c. 80–70 BC, died after c. 15 BC), commonly known as Vitruvius, was a Roman author, architect, civil engineer and military engineer during the 1st century BC, known for his multi-volume work entitled "De architectura". His discussion of perfect proportion in architecture and the human body, led to the famous Renaissance drawing by Da Vinci of "Vitruvian Man".
Quintus Claudius Quadrigarius Quintus Claudius Quadrigarius, Roman annalist, living probably in the 1st century BC, wrote a history, in at least twenty-three books, which began with the conquest of Rome by the Gauls (ca. 390 BC) and went on to the time of Sulla (fr. 84: 82 BC). The Clodius mentioned in Plutarch's "Life of Numa" 1.2 is probably identical to Quadrigarius.