He then moved to Christiania (now Oslo) and acquired burghership in 1832. In 1832, he founded the jewelers firm J. Tostrup, gradually expanding his business with more production equipment and better localities.
He subsequently moved to Christiania (now Oslo) and gained citizenship in 1832. In 1832, he established the jewelry business J. Tostrup, gradually expanding it with more equipment and improved local settings.