My oldest DE is a Gillette 1905 Double Ring; and my oldest Safety Razor (which is a Single Edge Lather Catcher using a wedge blade) is a Kampfe Bros Star (With Patent dates of 1880 and 1884) produced prior to 1900, exact date unknown. The Gillette Double Ring was the first DE safety razor (I believe), and it's story is well known. The Kampfe Bros Star safety razor models were the first non-disposable blade safety razors. I have several models ranging from this model to later models which have blade stops and can take modern GEM SE blades.
Here is a pic of my Gillette Double Ring:
Multiple pics of my Kampfe Bros Star lather catcher (Model 2B):
My Gillette Fat Boy or Adjustable as it was called then. It was the first new razor I bought as a teenager. This razor is older than many of the folks on B&B!
1904 Gillette Double Ring. The original owner ground down the baseplate a bit to resemble a New Improved. Very nice, smooth quality shave. Kinda like shaving with like any Old Type, only more aggressive with a pronounced blade gap.
The oldest razor that I own is a Gem Junior Bar lather catcher 1907-11 when MFG excellent mid range razor but on the milder side of that range! I still use this razor 2 or 3 times a month and enjoy the razor greatly!
Another razor Gem Damaskeene open comb 1912-15 - very rare to find but they are still out there. Excellent razor for a 3 pass shave(mid range but on the milder side of that range.)I use it 2 to 3 times a month and is a joy to use. They had it right over 100 years ago!!
Gem Vintage razors are excellent and they produced great razors that were competing with Gillette and a large host of other razor MFG's at the turn of the Century. GEM(A.S.R) sold 10's of millions of razors yet folks do not realize A.S.R corp was a huge world wide razor & blade MFG and remnants of the conglomerate are still around today like Personna & Gem brand blades.
Now Personna MFG's disposable razors and cartridge razors world wide and still compete with Gillette and other MFG's.