Short answers, pulled from the story.
The first known mention of a tribe called Saxones appears in Ptolemy's Geographia written in the 2nd century. This text places them north of the lower River Elbe in what is now Western Holstein.
Old Saxons imposed the death penalty on any man who married above his rank while severely condemning men who married below their station. Bastardy was not tolerated within these communities and intermarriage between Saxons and other Germans was frowned upon.
The traditional date for this invasion is 449 and is known as the Adventus Saxonum. Archaeological evidence suggests little long-term conflict occurred following the collapse of Roman defences on the Rhine in 407.
This event is understood to have happened on the 3rd of October 695 when both bodies were cast into the Rhine at Aplerbeck near Dortmund. Two priests called Ewald the Black and Ewald the Fair set out from Northumbria to convert the Old Saxons in 690.
The tribal lands were roughly divided into four kindred groups including Angrians Westphalians Eastphalians and Nordalbingians. These groups occupied specific territories along rivers such as the Weser Ems and Lippe within the broad plain of Old Saxony.