Accoding to the oldest document of the Lorsch codex, Erhartshausen, after remaining a mostly unimportant farming village until the early 20th century, grew strongly after the railway line from Frankfurt to Darmstadt was built several kilometers to the its east.
The oldest document of the Lorsch codex names it as 'Erhartshausen' ('Houses of Erhart'). The Lorsch Codex (Chronicon Laureshamense, Lorscher Codex, Codex Laureshamensis) is an important historical document created between about 1175 to 1195 AD in the Monastery of Saint Nazarius in Lorsch, Germany. 
