Complex sentence: The race was originally scheduled to be the opening round of the 1981 FIA Formula One World Championship however the ongoing FISA-FOCA war resulted in Fédération Internationale du Sport Automobile (FISA) insisting on a date change which was not acceptable to the race organisers.
Split into simpler sentences: The race was originally scheduled to be the opening round of the 1981 FIA Formula One World Championship. However, the ongoing FISA-FOCA war resulted in Fédération Internationale du Sport Automobile (FISA) insisting on a date change which was not acceptable to the race organisers.