Bertha, derived from the Old Germanic words 'berht' and 'helm', meaning 'bright' and 'helmet' respectively, was a popular name during the Middle Ages. It is often associated with strength and wisdom, reflecting its origins.
"The name Bertha experienced a peak of popularity between the late 1800s and early 1900s, with over 20 births recorded annually from 1904 to 1908, reaching a high of 25 in 1906. However, its usage began to decline after World War I, dropping below 10 births per year starting in 1917 and remaining low until the mid-1930s when it briefly regained some popularity. By the late 1940s and into the 1950s, Bertha was barely used as a baby name, with only 6 or fewer births recorded each year."