A chronology of the 107 symphonies 

There will probably never be a precise and flawless chronology of Haydn’s symphonies. Yet there were and are continuous attempts to find a series which at least approximates the historic sequence.
Among the oldest sources for this are the “Entwurf Katalog” (ca. 1765) and the “Haydnverzeichnis” (1805), which originate partly from Haydn’s own hand or were revised by him. Unfortunately, a categorisation of the works according to their origin was hardly a priority for him. It seems he was only interested in the completeness of the indexes. This circumstance as well as the fact that Haydn often dated his handwritten works (to the extent they still exist) using only the year have led to difficulties in determining the exact sequence (quite apart from the self-conception of publishers and collectors at that time who numbered works in accordance with their own needs). 
Thus scholarship is not seldom left with meticulous studies of the paper used for notation, the musicians list of personnel, the earliest transcriptions and naturally stylistic commentaries, etc., as aids for an – approximate - determination of the date of origin of many of Haydn’s works. 
An important attempt was undertaken to come up with a universally valid notation system by Eusebius Mandyczewski in his first complete critical edition published in 1908 by Breitkopf und Härtel. Anthony van Hoboken largely adopted this numbering system for his index of symphonies which appeared in 1957, after he made several additions. And in many cases he already took into account the studies by H. C. Robbins Landon, who had developed a chronology himself. Landon’s Chronicle did not appear before 1976, 1978 and 1980, however, and deviates considerably from the sequence of Mandyczewski and Hoboken. 
There are many other attempts by other scholars who have conducted comprehensive (or detailed) research on Haydn’s work such as Georg Feder, Stephen Fisher, Jens Peter Larsen, Horst Walter and the Joseph Haydn Institute in Cologne (which has been working on a chronological complete edition since 1960). James Webster has compiled a classification of symphonies in periods, for example. 
Attention should also be directed to the work Joseph Haydns Sinfonien bis 1774 Studien zur Chronologie (published in 1996) by Sonja Gerlach. She had already addressed the issue of chronology in several publications of the Joseph Haydn Institute in Cologne.
Nevertheless, the numbering of Haydn’s works in the Hoboken catalogue remains valid today. With respect to the impossibility of a flawless chronology mentioned at the start, this index despite any imprecision explainable due the state of the research at that time can be credited with having created an order which facilitates the identification of Haydn’s works worldwide. 
The retention of Hoboken`s numbering system in the repertoire and practice thus prevents Haydn’s extensive body of work from the hopeless chaos which would set in if his works were assigned new more correct numbering systems every few years. (Anton Gabmayer)

 Dr. Michael Fendre