The Old Germanic girl's name Ermintrude has a meaning that can be interpreted a few different ways. This ancient and archaic name comes from irm/erm, meaning "entire," and either traut, meaning "beloved," or thruth, meaning "strength." From this the total meaning could be "entirely loved," or "entire strength." However, it is possible the name refers to Ermen, the Germanic god of war, and thus her meaning would be "Ermen's maiden." Her name can also be spelled a handful of other ways, including Ermentrude, Ermyntrude, Ermentraude, and other variants with an I replacing the first E. Ermengard (Irmingard) is another variant meaning "whole enclosure." Ermintrude was used occasionally until the 19th century.
There are two Ermintrudes you should know about. The first is Ermentrude of Orleans, Queen of the Franks and wife to Holy Roman Emperor / King of West Francia. (Interestingly, her mother was named Engeltrude.) She and her husband Charles had ten children. The second Ermintrude is actually Erminethrudis, a nun from Merovingian aristocracy, who it seems is most known for leaving us with a will that gives an example of the times. There is also an Ermintrude in Terry Pratchet's novel Nation.
The name Irma, which follows today's 100 year rule since it was most popular in 1911, is simply the first element of Ermintrude (Irmintrude) meaning "entire, universal." It is related to the super popular Emma, being that Emma originally came about as a short form of names like Ermintrude, although Emma didn't really become stable until the Norman conquest. About the time Emma was increasing in use in the 18th century, Ermintrude was dying out. Some may recall Irma was the name of April's best friend in "Teenage Mutant Ninja Turtles," and there is an Irma Pince in Harry Potter. Irma is also a character in The Adventures of Tintin. In the 40's Irma gained a little popularity thanks to the radio show, and later television and movie version, "My Friend Irma." Irma featured in a few other places in the 50's and 60's, including the film "Irma la Douce." Irma is traditionally pronounced EER-mah in other countries, URR-mah in English speaking countries. Irma last ranked in 1995. Imma and Irmina are two rare variants of Irma.
For those looking for something more modern, Trudy has often been used as a nickname for Ermintrude and Gertrude. It means "strong spear" and could easily work as a vintage revamp today. Trudy is a name most are familiar with, yet it hasn't been in the top 1000 for over a decade. It had an incredible rise and fall - from about 5 girls per year in the late 1800's/early 1900's to almost a thousand per year in the 1940's and 1950's, then back down to less than 20 in 2013. To further make Trudy accessible today, you could further reduce the name to Tru. There have also been several namesakes, including Australian fantasy writer Trudy Canavan, British women's rights activist "'Trudie" Gertrude Denman (a Baroness), and three actresses. In fiction, Trudy appears in many places from Disney Comics to the TV show "Mad Men."