Although gifts have traditionally been given for wedding anniversaries since medieval times, Emily Post was the first to publish a list of suggested anniversary gifts.
Her first etiquette guide, published in 1922, contained suggestions for the first, fifth, tenth, fifteenth, twentieth, twenty-fifth and fiftieth years of marriage. When her book was reprinted in 1957, that list was expanded to include suggestions for each of the first 15 years and for every five years after that.
As time went on, even this list was broadened by other authors to include gifts for every year from the first to the twenty-fifth, plus every five years through the 75th wedding anniversary.
Another list, found on many florists websites, offers flower suggestions as anniversary gifts.
I have been unable to find an acknowledged source, but the list of Anniversary Flowers was probably created and documented by florists as wedding anniversaries became a popular gift giving occasion.
Based on our research, there doesn't seem to be one acknowledged and authoritative list. However, the Anniversary Stones Gift List has been endorsed by the Jewelers of America, the American Gem Society, the American Gem Trade Association, and the Gemological Institute of America (GIA). This list differs from the Traditional and Modern lists in that it only includes gemstones and precious metals.
The Alternate List was compiled from various books and internet sources. These alternate stones appear to have little acceptance as suggested gifts but are listed here for completeness.
The Traditional Anniversary Gifts List is based on Emily Post's original suggestions from her book "Etiquette", while the Modern Anniversary Gifts List is no doubt based on the expanded list from the edition reprinted in 1957 that includes additions from various other sources.