The Trials of Apollo North America to restore the remaining four Oracles and defeat the triumvirate of Roman emperors-turned-Gods, while also being helped by Leo Valdez, the now-mortal Calypso and Festus the bronze dragon. "The Burning Maze" is the third book in the series. It released on May 1, 2018. The book follows Lester Papadopoulos/Apollo, Meg McCaffrey and Grover Underwood while they try to rescue Herophile, an Oracle that speaks only in puzzles, from the Roman emperor Caligula and his talking horse, Incitatus. In the process, they met some strixes that feed only on blood, which they finally repel using strawberries. While sleeping, Apollo
Xanten Horse-Phalerae ('while Pliny was Prefect of the cavalry'). This suggests that these horse-phalerae belonged to a cavalryman under his command when Pliny was stationed in Germania Inferior in approximately 50 AD. The set of horse-trappings is made of about 60 silvered-bronze phalerae and forms part of a decorative equestrian harness that is only partly preserved. Organic material such as leather has not survived but enough roundels have to enable a partial reconstruction of the set in the museum. One of the phalerae has the bust of a Roman Emperor, but it is difficult to determine which emperor is represented from the