The Österling/Osterling (Sweden/Perú) & Álvarez-Calderón (Spain/Perú) genealogy and its 'six degrees of separation', a collaborative multi-generational effort, which began more than a century ago, documenting branches of the family in Europe starting in the 12th century. Family members are currently located in Asia, Europe and N. and S. America. Twenty-seven generations have been documented on one branch, assigning our oldest ancestor the number 25,296,896 (Sosa-Stradonitz System) at year-end 2009. There is no connection between the Peruvian and Mexican Álvarez-Calderón families. The Peruvian Álvarez-Calderón last name dates back to the early 18th century (Spain) while the Mexican Alvarez-Calderón last name presumably dates back to the early 20th century; nevertheless both families joined the two last names in similar fashion and order: Álvarez and Calderón.