ok ppl your probally gonna think this is really stupid but this
Three rings for the Elven-kings under the sky;
Seven for the Dwarf-lords in their halls of stone;
Nine for Mortal Men doomed to die;
One for the Dark Lord on his dark throne
In the Land of Mordor where the Shadows lie;
One Ring to rule them all, One Ring to find them,
In the Land of Mordor where the Shadows lie;
One Ring to bring them all and in the darkness bind them
Who made these rings and Why?
The One Ring was made by Sauron alone, and in secret.
The Seven and the 9 were made by Sauron and the Elves together in Eregion. Celebrimor was the cheif smith and Sauron tempted them (long story read the books) Sauron then left. Celembimbor made the Three w/o Saruon's assistance (but using the knowledge that he had gained from him). That is why the Elven rings were able to be kept secret and hidden.
So for a time line:
S.A.1500 The 7 and the 9 are forged.
S.A.1590 The 3 are forged.
S.A. 1600 the One is forged.