Editing IJssel (section)

== History ==
{{See also|Zuiderzee}}
[[File:Deventer 1567.jpg|thumb|left|The IJssel at [[Deventer]] in 1567]]
The name ''IJssel'' (older ''Isla'', ''Isala'', from *''Īsalō''), is thought to either have been derived from a [[Proto-Indo-European]] root ''*eis-'' "to move quickly" ([[Old Norse]] ''eisa'' "to race forward", [[Latin]] ''ira'' "anger")<ref>J. de Vries, ''Etymologisch woordenboek''. Utrecht: Het Spectrum, 1959</ref> or a possible [[Old European hydronymy|Old European]] stratum source.<ref>[[Xavier Delamarre|Delamarre, Xavier]]. ''Dictionnaire de la langue gauloise''. Paris, Ed. Errance, 2003.</ref>

Before the [[Roman Warm Period]], the [[Zuiderzee]] in highly glaciated times was a brackish, sometimes tidal, very broad set of [[mudflats]], the ''Vlies'' (Latin: ''Flevo'').  The IJssel and [[River Amstel|Amstel]] kept a saline-freshwater balance, and northward flow, enabling islands and banks to build up.  Among these are rare zones just above sea level: [[Kampen, Overijssel|Kampen]], [[Elburg]] and north-east bank once wooded strip from Nijemirdum to [[Stavoren]].

However, the North Sea, locally to form (or re-form) the Zuiderzee, reasserted itself &ndash; the so-called [[Dunkirk transgression]]s.

By the time these were tamed ([[terraforming|terraformed]]) the IJssel had formed many of its new short [[distributary|distributaries]] to dissipate its flow. The submerged old delta is traceable out from its sea level elevation point at [[Zwolle]] throughout the broadest parts of the [[IJsselmeer]]; the lands of [[Emmeloord]], [[Lelystad]] and south of [[Dronten]] are relatively recent reclamations. They were continuations of these old, broad troughs, and lie six metres below sea level.

The name [[Vlie]] refers to a [[strait]] between sea [[island]]s, [[Vlieland]] and [[Terschelling]]. It seems that the firmly below-sea-level excoriations in the far north (the ''Groote Vliet'') by [[Medemblik]] and the [[IJ (Amsterdam)|IJ]] (near [[Amsterdam]]) were all deep parts of the same body of water in the height of the Roman Warm Period and Medieval Dark Age sea rises (transgressions).  Most of the surrounding basin of the vast harbour-like body of water of the Netherlands is reclaimed from it (nationally called polderisation; in England called the making of a fen).

The river was a natural barrier and in April 1945 was stormed by assault troops of the Allied armies liberating the Netherlands from the occupying forces of [[Nazi Germany]].<ref>Stacey, C. P. ''History of the Canadian Army in the Second World War: Volume III The Victory Campaign''</ref>

=== The IJssel as the lower part of the Oude IJssel ===
{{main article|Oude IJssel|Canal of Drusus}}
Most of the IJssel was the lower part of the small river [[Oude IJssel]] (lit. "Old IJssel", [[German language|German]] ''Issel''), that rises in Germany and is now a 70&nbsp;km tributary. The [[Canal of Drusus|connection between the Rhine and IJssel was probably artificial]], allegedly dug by men under the [[Ancient Rome|Roman]] [[general]] [[Nero Claudius Drusus]] {{circa}} 12 BCE as a defence against [[Germanic tribes]] and to let Roman ships carry troops along it.<ref>{{cite book |editor-last=ter Laan |editor-first=K.|display-editors=etal|title=Van Goor's aardrijkskundig woordenboek van Nederland |year=1942 |publisher=Van Goor Zonen |location=[[The Hague|Den Haag]]|language=nl }}</ref>

The Oude IJssel is the second-largest contributor to the flow of the river, after the Rhine.

The source of the Oude IJssel is near [[Borken, North Rhine-Westphalia|Borken]] in [[North Rhine-Westphalia]], Germany. First it flows south-west until it nearly reaches the Rhine near [[Wesel]]; then it turns [[boxing the compass|west northwest]]. After skirting [[Isselburg]] it crosses the border with the Netherlands. The river then flows through [[Doetinchem]] and joins the IJssel at Doesburg.