|Style over substance|
An alternate historical chronology is a historical approach that discards or rearranges elements of the commonly-accepted history of human civilizations and replaces them with new narratives. Alternate historical chronologies can be used to prop up ideological or political claims, to reap profits from book sales, or simply to attack an established branch of knowledge for being non-inclusive. These chronologies frequently present themselves as self-enclosed systems that derive their authority from the creator's personal charisma. Revisionist histories--dissenting views within the academic discipline of history--should not be included within this category, provided that they are based upon logical arguments, verifiable data, and are formed by individuals conversant in accepted historiography.
Alternate historical chronology is not to be confused with alternate historical fiction.
 Compelling narratives
Alternate histories, though false, can be particularly compelling because of their broad scope and their ability to pick and choose evidence used. The cherry picked evidence can easily sway most people into thinking that such alternate histories may be genuine - while on the other hand it may take some specialist or far wider reaching knowledge of history to realise how wrong they can be. Cherry picking historical evidence, especially to say that certain periods didn't even exist, is particularly bad because it is impossible to separate historical evidence in such a manner; we could have no evidence of Europe existing between 500 and 1000 CE, but that doesn't mean that those dates "didn't exist" because we'd also have to show the same for every other country and continent on the planet. In addition to selective evidence, alternate historical chronologies can be especially attractive because of the compelling narratives that they can generate. Defying established history and replacing it with what is essentially fiction can be done to suit a range of political ideals or prejudices. As with most conspiracy theories, one of the primary drivers for people to believe alternative histories is the need to feel that they know better or more than everyone else, particularly established experts and "official" stories. While most "real" historians are aghast at this silliness, sometimes the proponents of these theories make inroads into popular media.
An honest use of such alternate chronologies is within speculative fiction (the more general euphemism for science fiction). In such cases the author is honest about such changes in the sense that the work is presented as fiction, and that they have altered history to make for a better story. Usually such alterations are quite noticeably large and dramatic compared to the often subtle changes by alternate historians, who mess around with established dates and ancient history but don't do anything as spectacular as claiming Nazi Germany won the Second World War.
 "Theorists" and their "theories"
Please note that none of these "theorists" are trained historians.
 Anatoly Timofeevich Fomenko
Fomenko is considered a top mathematician, being a member of the Russian Academy of Sciences but he is most famous for his historical work, revising orthodox historical chronology. Fomenko's New Chronology asserts that most of recorded history was composed by Church mandate, for the purpose of validating the historical placement of Biblical events, and that real history only begins in the 11th century-CE! He does not explain away the Old Kingdom of Egypt and Ancient Mesopotamia. His chronology is commonly rejected among professional historians, including most fellow Russian academics, as being non-historical in nature.
 Heribert Illig
Illig's phantom time hypothesis consists of the idea that several pre-1000 CE centuries, specifically the period 614-911 CE, were fabricated and "inserted" into the historical record. Supposedly, this took place at the command of Holy Roman Emperor Otto III who wished to be on the throne come the "millennium".
This theory would eliminate or displace, among other things, a fair number of the Merovingian ruling dynasty and most of the Carolingians (including Charlemagne), the Battle of Tours in 732, the Viking raids of the 8th and 9th centuries, and the establishment of both the Duchy of Normandy and the Kingdom of East Francia, which later became the Holy Roman Empire.
Illig's theory is geographically limited to France and Germany, so it is unclear how he intends to account for the events that are supposed to have happened elsewhere in the world during the period in question.
Velikovsky's ideas in no way relate to those of Fomenko or Illig. Attempts have been made throughout history to verify the accuracy of Biblical scripture through the use of falsified historical information. Velikovsky's ideas are an example of this trend.
Velikovsky's so-called Revised Chronology was an attempt to reconcile the history of the ancient Near East, particularly that of Egypt, with the historical accounts found in the Bible. A central concept for Velikovsky is that of alter egos: historical characters who are named by different names in different sources, but actually refer to the same person. In this way, Queen Hatshepsut becomes the Queen of Sheba, and Thutmose III King Shishak of 1 Kings 11:40. On average, the Revised Chronology requires that the commonly accepted chronology of Egypt be changed by about 500 years.