[1] Clausen has been termed the "premier 19th century architect" of Davenport, Iowa.
[3] His official name in Eckernförde was: Fritz Georg Martin Clausen.
[5] In addition to his architecture practice, Clausen was an alderman of the city of Davenport, and was instrumental in setting up the Davenport paid fire department in 1882, with three new fire appliances.
[6] After his arrival in America, Clausen initially worked as a draftsman for Thomas W. McClelland a local architect of some note.
[2] He opened his own firm - F.G. Clausen - in Davenport in 1871,[4] working alone until 1896, and then partnered with Parke Burrows until 1904.