The Rosarium Philosophorum or The Most Precious Gift of God (Rosarium philosophorum sive pretiosissimum donum Dei ) was first printed in Frankfurt (published by Cyriacus Jacob, 24 March 1550) as part II of About Alchemy: Little Works of Many Early Philosophers (De Alchimia Opuscula Complura Veterum Philosophorum). It is an anthology comprising many short texts on alchemy by various writers, together with twenty woodcut illustrations.

The Latin word Rosarium translates as ‘Rose Garden’ and ‘Rosary.’ Rose Garden is thought to refer to the structure of the volume as a collection of sayings and ideas (of philosophers). However, the word Opuscula in the long title translates as ‘little works’ and also as ‘trifles’ and is, for example, used for several volumes of little works by Thomas Aquinas. Why, therefore, would the term Rosarium be used to describe what is already understood by the word Opuscula?

When Rosarium translates as 'Rosary’ it brings with it a connection to garlands/crowns of roses and particularly to the Virgin Mary and of Catholic Marian devotion. With a capital ‘R’ ‘the Rosary’ refers to a collection of prayers. The prayers that make up the Rosary are organised in clusters of ten Hail Marys, called ‘decades’. Each decade is preceded by one Our Father, followed by one Glory Be and one O my Jesus. Each complete Rosary makes a crown of roses for the Virgin Mary. The Rosary involves a meditation on the mysteries of joy, of sorrow, of glory and of light.

When ‘rosary’ translates with a lower case ‘r’ it refers to a set of prayer beads (rosary beads). Rosary beads are a material aid to remembering the number and sequence of prayers and mysteries.

Etymologically Rosarium possibly comes from rosa ‘rose’ and arium ‘thing connected with’, ‘place for’, ‘place that holds’. Here rosa means a prayer or devotion. However, this leaves us with rosa arium/rosaarium which isn’t quite the word we’re exploring.

I propose that etymologically Rosarium comes from ros ‘dew’ and arium ‘thing connected with’, ‘place for’, ‘place that holds’. So Rosarium Philsophorum becomes ‘Place that holds the dew of the philosophers’ and ‘Thing connected with the dew of the philosophers’. Significantly, ‘dew’ is listed as one potential source of the Prima Materia. Prima Materia (The First Matter) is the starting material for the entire work of Alchemy.