There have been three major fiction magazines called Argosy. The earliest was founded by Alexander Strahan in 1865 (and later published by Ellen Wood's as a 'serious monthly magazine' up until 1901. The most famous was the American magazine started by Frank A. Munsey that ran from 1882 to 1979 (with a couple of revivals since). This UK magazine, which had no connection (beyond the name) with either of the other two periodicals, ran for a very respectable 571 issues from 1926 to 1974 (albeit with two distinct publication phases).
From the start the UK Argosy was predominantly intended as 'a reprint magazine of the world's best short stories.' For the first 14 years it was a fairly staid pulp magazine with covers that typically included a single sailing ship. Then in 1940 there was a dramatic change in format as the magazine became a digest and began a new numbering system.
[Source: Galactic Central]