The composition for solo horn by Viktor Kalabis titled Invocation is one of the latest opuses of the composer.<br>
It was written in 2000 as a result of the commission from the 6th International Horn Competition, which formed a part of the 36th International Music Festival Brno.  The composition was included among compulsory pieces for the competition, which only reflects the fact that the piece is quite a demanding one and therefore, it is best suited for mature and technically able performers.<br>