Although the treaty's Santo Thome island has not been identified, its "Islas de las Velas" (Islands of the Sails) appear in a 1585 Spanish history of China, on the 1594 world map of Petrus Plancius, on an anonymous map of the Moluccas in the 1598 London edition of Linschoten, and on the 1607 world map of Petro Kærio, identified as a north–south chain of islands in the northwest Pacific, which were also called the "Islas de los Ladrones" (Islands of the Thieves) during that period. Their name was changed by Spain in 1667 to "Islas de las Marianas" (Mariana Islands), which include Guam at their southern end. Guam's longitude of 144°45′E is east of the Moluccas' longitude of 127°24′E by 17°21′, which is remarkably close by 16th-century standards to the treaty's 17° east. This longitude passes through the eastern end of the main north Japanese island of Hokkaidō and through the eastern end of New Guinea, which is where Frédéric Durand placed the demarcation line. Moriarty and Keistman placed the demarcation line at 147°E by measuring 16.4° east from the western end of New Guinea (or 17° east of 130°E). Despite the treaty's clear statement that the demarcation line passes 17° east of the Moluccas, some sources place the line just east of the Moluccas.