In pre-Christian times and in the first century after Christ there was no trace of large or enclosed settlements in the area of modern Mariazell. The large number of Illyrian and Celtic mountain and river names in the region, such as for example the Erlauf, however suggest small settlements by these tribes. The salt springs in Halltal were not unknown to these groups.
By 16 AD the Romans were using the salt roads of Halltal and the Traisental. According to some accounts, there also was a Roman road going to Neuhaus.
In 600 the Slavs, under the leadership of the Avars, took control of the land and settled in the mountain region and began farming. The expansion of these peoples also accounts for the existence of some of the town and mountain names today.
In 1025, Emperor Conrad II gave his sister-in-law Beatrix, married to Adalbero of Eppenstein, parts of the county in the Mürztale as a gift. With this gift came around 100 Huben, which belonged to the territory of the future market of Mariazell. There was an argument for one year over this gift involving the Reichsgericht and even the Pope. Eberhard, Archbishop of Salzburg, decided in 1151 in favor of the Monastery of St. Lambrecht. It was allowed to control part of the parish territory of Mariazell and the of dominion of Aflenz. The date, December 21, 1157, is taken off a document from Pope Adrian IV, still traditionally celebrated as the date of Mariazell's establishment, even though it cannot be proven historically.
In 1157, Monk Magnus came into the Zellertal with a lime-tree wood statue of the Virgin Mary and founded the first chapel there, around which the town later grew. The town's name derived from the description "Mary in the cell", i.e. in the monk's chapel.
In 1344, Mariazell was elevated to the status of market town.
Between 1340 and 1380, the church was rebuilt in the gothic style.
In 1420, the Turks came to Mariazell for the first time and burned the
