Clausula rebus sic stantibus doctrine and development of contemporary theory of breach of causa in German law at the end of XIX<sup>th</sup> - beginning of XX<sup>th</sup> century
Institution of the contract foundation breach was brought in the German Civil Code text just in 2001, but in fact it appeared long ago and developed in the context of jurisdiction and legal thought on the basis of the «circumstances invariability» doctrine (clausula rebus sic stantibus). The article is devoted to the history of the formation of this German civil law institution.