A volcanic island in the Sea of Seas, implied to be the last of a series of islands. Ecba was home to the Temple of Orithena from -2850 to -2621, the center of Arbran mathematics and culture. The southern slope of the volcano that formed the island erupted in -2621, burying the Temple of Orithena and destroying a harbor on the island's southeastern coast. The theors who fled the eruption became the very first Peregrins.
The island was owned by various empires, private owners, and trusts, until approximately 2500 A.R., when it was purchased by the Lineage. Around 3000 A.R., the Lineage began to excavate Orithena and construct a cloister around it.
In 3690, Fraa Orolo sought shelter on Ecba after his Anathem. He was found there by Fraa Erasmas, Cord, Yul, Gnel, and Sammann. Erasmas described Ecba as "beautiful, in a hot and harsh way" and approximately round, taking around two hours to circumnavigate. The group camped at a small rock-bound cove on the northeastern shore of the island, one of a series of coves separated by fingers of volcanic rock. On the northwestern shore was a small town built around the island's "only surviving harbor." The town is the location of the terminal for the ferry to the mainland and receives water from a solar-powered desalination plant. The southern slope of the island was the site of the Temple of Orithena and it's accompanying cloister, accessible by a small dirt track. The road along the southern coast is described as a dirt track crossing a fan of ash and rubble left over from the eruption of the volcano.
Orolo used the analemma at the Orithena dig as a beacon for the probe sent by the Fulcrum, and event later known as the Visitation of Orithena. Consequently, the Pedestal used a rod to trigger another eruption of the volcano, burying the Orithena dig and cloister. The Saecular military rescued most of the inhabitants of the cloister by plane. One notable exception is Orolo who martyred himself by giving up his spot on a plane for the body of the dead Laterran Lise.