In Rome he studied art under Professor
Modesto Faustini in 1887; Faustini imparted an appreciation for the
Italian masters that influenced Rosenkrantz's work. There was a dreamy, emotional quality to his work throughout his artistic career as a painter and stained glass artist. Two years later he studied under
Jean-Paul Laurens and
Benjamin Constant at the
Académie Julian in
Paris. From 1898 he stayed in London, where he developed his reputation as an artist. In London, Rosenkrantz joined the
Anthroposophic Society. In 1912 he met Austrian philosopher
Rudolf Steiner personally. Two years later he and his wife moved to Dornach,
Switzerland to participate in the decoration of the anthroposophical center Goetheanum with other artists. Steiner, who taught Rosenkrantz of colors intrinsic properties, Rosenkrantz returned to London with his wife after Steiner died in 1925. He then took up several artistic pursuits for Anthroposophic theatres: he designed costumes, created stage decorations and decorated the interior of 2 theatres. He also worked as a teacher and held annual exhibitions. Rosenkrantz is ==Later years==