Isis belongs among the foremost and oldest of Egyptian goddesses. Her name Isis means "throne" from which her husband/brother Osiris ruled. The oldest location of its local cult was the first residence of the Egyptian kings, at This. Isis was the goddess of fertility and motherhood, a personification of the Earth or even better, the whole of nature. Isis is often depicted with a baby in her arms or lap.

The trinity, Osiris and Isis and their son Horus, had become a cult which had spread around the ancient world including Greece where it had gained a certain influence. In Rome, it was celebrated on the 5th day of March which coincided with the beginning of sea journeys.

Isis is associated with the Virgin Mary in many forms, most of all in fertility, both in relation to nature, where the present-day Egypt, Syria, Lebanon, Iraq, Jordan and Israel were among the places where the time about five thousand years ago were good conditions for the birth of civilization, because it was a very fertile region called the Fertile Crescent.

Isis gave birth to Horus, Mary with the God Jesus. With the rediscovery of Isis appear Lenz and its attribute in the form of horns, which is nothing more than a half-moon, on which Mary stands.

At the request of artist Amalie Bensinger, who wanted a statue of the Virgin Mary for the monastic island of Reichenau/Baden Wuerttemberg, where Benedictines lived, Lenz outlined several designs for future Isis-Madonna statues, as he himself called them. A year later, in 1872 a plaster cast wax model by Lenz was exhibited in Nuremberg.

Plečnik highly valued the plaster model and proclaimed its eternal relevance. It is evident from the photograph from 1912, where the plaster casting of Isis stands on a shelf behind him. In the same year, the model was also cast in bronze.

In 2006, Beuron authorized three new bronze castings. One of them is in the Landesmuseum in Karlsruhe, the second with Lenz's great-niece, opera singer and artist Veronica Lenz-Kuhn in Munich, and the third is in a private collection in Prague.