For over a hundred years maps showed California as an island off he coast of the North American continent, as in the map below. 

P. Mark Anton Kappus

     Slovenia issued two stamps to commemorate the 500th anniversary of the discovery of America. The higher value depicts an unidentified old map of the Gulf of Mexico with a dedication to Christopher Columbus.
     The lower value shows an unidentified map of California and Sonora with the image of a missionary and Indians. This commemorates the work of the Jesuit missionary P. Mark Anton Kappus (1657-1717) of Kamna Gorica who worked in the Sonora country (northern Mexico) at the end of the 17th century and the beginning of the 18th century.

     In a letter dated 8 June 1701 that Kappus sent to his friend Philippus Alberth in Vienna Kappus was the first to report that California was not an island, as was generally believed at the time, but rather a peninsula, and thus a part of the North American continent.

Fr. Eusebio Francisco Kino

     Eusebio Francisco Kino (1644-1711) was a Jesuit missionary, explorer, and director of the Spanish missions among the Pima Indians. He arrived in New Spain in 1681 and established his headquarters at Nuestra Señora de los Dolores in Senora. He founded a number of missions in Primería Alta (present-day northern Senora, Mexico and southern Arizona). His explorations of the mouth of the Colorado River in 1701 convinced him that Baja California was a peninsula, not an island as was believed by many. His map of the area, drawn in 1705, was the standard reference map for more than a hundred years.

     For futher information on Fr. Kino and his correction of the Island California error, see: Bill Warren, "Map Maker on a Mission," Exploring Mercator's World: The Magazine of Maps, Geography, and Discovery. 7:4(2002)24-35.

Ferdinand Konšćak

     World-known explorer Ferdinand Konšćak, son of a senior military officer, was born in Varaždin in 1703. Determined to become a missionary, he applied to the Jesuit general in Rome for six years, asking to be sent to India. Finally he was chosen for Indian missions in Mexico. Later he was sent to a mission in Lower California, and from 1733 he spent 26 years at San Ignatio as a missionary, visitor and superior, and also as an explorer-geographer. He organized and led three major expeditions to explore the northern parts of Lower California, in 1746 by sea, and in 1751 and 1753 by land. The objective of the first expedition was to prove that Lower California is a peninsula, which Konšćak did, and to find springs of fresh water and pastures for further missions in the north. After the 1746 expedition he published a map of Lower California, as far as the mouth of the Colorado in the Golf of California. This map was later included in many books and was used until mid-nineteenth century as the official American map.