The Mariana Islans (also the Marianas; up to the early 20th century sometimes called Ladrones Islands, from Spanish Islas de los Ladrones meaning "Islands of Thieves") are an archipelago made up by the summits of 15 volcanic mountains in the north-western Pacific Ocean between the 12th and 21st parallels north and along the 145th meridian east. The islands were named after Spanish Queen Mariana of Austria in the 17th century, when Spain started the colonization of the archipielago.