Catholic missionary Father A. Erdland, from the Sacred Heart Jesu Society based in Hiltrup, Germany, lived on Jaluit from around 1904 to 1914. He was very interested in the islands and conducted considerable research on the Marshallese culture and language. He published a 376-page monograph on the islands in 1914. Father H. Linckens, another missionary from the Sacred Heart of Jesu Society visited the Marshall Islands in 1904 and 1911 for several weeks. He published a small work in 1912 about the Catholic mission activities and the people of the Marshall Islands.

What Catholic group was Father Erdland a part of?