In the years between 1912 and 1916, the Danish artist and graphic designer Gerhard Heilmann published a series of articles in the journal of the Danish Ornithological Society. From the outset, Heilmann's work aroused international interest, and in 1926 it was published in English as The origin of birds, setting the international agenda for research in bird evolution for the next 40 years. In Denmark, however, Heilmann's highly original work was generally ignored or even ridiculed by zoologists. This article demonstrates how Heilmann's artistic abilities played an important role in securing him international renown as a palaeontologist, while at the same time his lack of scientific credentials led to his complete isolation from the Danish zoological establishment. And it suggests that Heilmann's unyielding efforts to solve the riddle of bird evolution in the borderland between art and science, reflected a deeply felt emotional and spiritual need to counteract the religious dogmatism that had permeated his childhood and early youth, leaving memories and experiences that remained vividly painful throughout his life.