The history of the German language as separate from common West Germanic begins in the Early Middle Ages with the High German consonant shift. Old High German, Middle High German and Early New High German span the duration of the Holy Roman Empire. The 19th and 20th centuries saw the rise of Standard German and a decrease of dialectal variety.
The earliest testimonies of Old High German are from scattered Elder Futhark inscriptions, especially in Alemannic, from the 6th century, the earliest glosses (Abrogans) date to the 8th and the oldest coherent texts (the Hildebrandslied, the Muspilli and the Merseburg Incantations) to the 9th century.
Middle High German (MHG, German Mittelhochdeutsch) is the term used for the period in the history of the German language between 1050 and 1350. It is preceded by Old High German and followed by Early New High German. In some older scholarship, the term covers a longer period, going up to 1500.
When Martin Luther translated the Bible (the New Testament in 1522 and the Old Testament, published in parts and completed in 1534) he based his translation mainly on this already developed language, which was the most widely understood language at this time. This language was based on Eastern Upper and Eastern Central German dialects and preserved much of the grammatical system of Middle High German (unlike the spoken German dialects in Central and Upper Germany that at that time had already begun to lose the genitive case and the preterite). In the beginning, copies of the Bible had a long list for each region, which translated words unknown in the region into the regional dialect. Roman Catholics rejected Luther's translation at first and tried to create their own Catholic standard (gemeines Deutsch) — which, however, differed from 'Protestant German' only in some minor details. It took until the middle of the 18th century to create a standard that was widely accepted, thus ending the period of Early New High German.