The Son of Neptune released on October 2, 2012 and "The House of Hades" was released on October 8, 2013 The Blood of Olympus was released on October 7, 2014. The Son of Neptune The Son of Neptune is a 2011 fantasy-adventure novel written by American author Rick Riordan, based on Greek and Roman mythology. It is the second book in "The Heroes of Olympus" series, preceded by "The Lost Hero" and followed by "The Mark of Athena". The story follows the adventures of amnesiac Percy Jackson, a demigod son of Poseidon, as he meets a camp of Roman demigods and goes to Alaska
Neptune (mythology) In this respect he was the equivalent of Mars, Janus, Saturn and even Jupiter among Latin tribes. Salacia would represent the virile force of Neptune. The Neptunalia was the festival of Neptune on July 23, at the height of summer. The date and the construction of tree-branch shelters suggest a primitive role for Neptune as god of water sources in the summer's drought and heat. The most ancient Roman calendar set the "feriae" of Neptunus on July 23, two days after the Lucaria of July 19 and 21 and two days before the Furrinalia of July 25. Georg Wissowa had