It might actually be that there are no precursors; that nothing like this has happened before.
While a lot more information is needed before investigators can be sure of the cause, there are precursors that suggest a pattern.
For this reason I shall spend little time on the famous theories of the origins of the Greek Romances and on their precursors.
I only maintain that for me these two things are invariably the precursors of misfortune.
They are the precursors in the great army of destruction, and often finish the dreadful work themselves.
In all these signs Costal recognised the precursors of a storm.
These two pursuits have thus in a manner been the pioneers and precursors of civilization.
Marlo and Rodbertus are sometimes spoken of as the precursors of German socialism.
It is for this reason that I have made use of the first chapter to say a few words on the precursors of this movement.
There is much to be learned from the precursors I have mentioned.
precursor pre·cur·sor (prĭ-kûr'sər, prē'kûr'sər)
One that precedes and indicates something to come.
One that precedes another; a forerunner or predecessor.
A biochemical substance, such as an intermediate compound in a chain of enzymatic reactions, that gives rise to a more stable or definitive product.