after world war i, milanković returned to belgrade with his family on 19 march 1919. he continued his professorial career, becoming a full professor at the university of belgrade. from 1912 to 1917, he wrote and published seven papers on mathematical theories of climate both on the earth and on the other planets. he formulated a precise, numerical climatological model with the capacity for reconstruction of the past and prediction of the future, and established the astronomical theory of climate as a generalized mathematical theory of insolation. when these most important problems of the theory were solved, and a firm foundation for further work built, milanković finished a book which was published in 1920, by the gauthier-villars in paris under the title "théorie mathématique des phénomènes thermiques produits par la radiation solaire" ("mathematical theory of heat phenomena produced by solar radiation"). immediately after the publication of this book in 1920, meteorologists recognized it as a significant contribution to the study of contemporary climate.