This company is one of the front-runners of the fountain pen renaissance, established in 1990 by Geroge Kartsotis and named for the year of his birth rather than as a reference to the famous Parker model. There is some room for subjective debate as to whether the company consistently lives up to its slogan “Life is too short to carry an ugly pen!” but they do at least produce interesting ones. The Retro element of the name is not a profound, studied reproduction of past objects; it is more in the direction of the Steampunk movement’s “something that you would believe came from then” with the then in question being the mid-twentieth century (which I guess means Dieselpunk, doesn’t it?). Most notably retro in Retro 51’s output are their desk bases, which are modeled very closely upon the Esterbrook “Eight Ball.”
As of this writing in 2017, the fountain pen selection, and indeed the entire product line of Retro 51, is scaled back from a high point of a few years previous, when there were several models of fountain pen. Their current offerings are mainly variations on a few body shapes, only one of which is a fountain pen. This is probably a rational response of a relatively small player in a large market; sticking to the known sellers, and since Visconti has pulled a similar trick with its Van Gogh and Rembrandt lines, Parker with the 75, and Sheaffer with the Targa, one hesitates to say anything against it.
Models I’ve examined: