Van Royen was born in an upper-class family in
Leiden where his father
David van Royen (1699–1764) was a well-known jurist, administrator and
Leiden University librarian. He studied medicine and became a physician in 1752. He published a book,
Oratio de hortis publicis præstantissimis scientiae botanicae adminiculis in 1754 and became a professor of botany and director of the Hortus Botanicus Leiden in the same year. He was elected to the
Royal Society in 1752. He greatly added to the herbarium collections and the Van Royen Herbarium has been considered important for
taxonomic purposes as it includes numerous
types of biological species. He was a correspondent of
Carl Linnaeus. ==Botanical abbreviation==