Dorothea Gerard was born in Scotland, a daughter of Archibald Gerard of Rocksoles, Scotland, and his wife Euphemia Robison, and younger sister of Jane Emily Gerard. She was educated by nuns in Graz, Austria. In 1886, she married Julius Longard de Longgarde, an Austrian military officer, and lived with him in Vienna and Galicia. She became a novelist and romance-writer with a piercing eye for national and ethnic divides, anti-Semitism, and other forms of prejudice. She also wrote a social study of the pan-European officer class of the Imperial Austrian army. Dorothea wrote first in collaboration with her elder sister and later independently. Her writing style was influenced by the works of Ouida and Oscar Wilde. She published well over 30 novels, many of them aimed at English speakers travelling abroad.