There were originally 19 –
The Elves of Eregion forged many rings, including nineteen Rings of Power. But Sauron had deceived them, for he made the One Ring for himself, which was the master of the rest.
However Sauron's plan failed: the elves discovered his plot and discarded their Rings until they could be shielded from his influence. Sauron then waged war upon the Elves. He captured all the Rings of Power except three.
7 were given to the Dwarf Lords and 9 to Human Kings –
The Rings of Power were the masterwork of the elven-smiths of Eregion headed by Celebrimbor who was descended from Fëanor. The impetus for their creation came from Sauron, who could at that time still assume an appearance fair enough to deceive the Elves. A total of nineteen Rings of Power were forged by the Elves, sixteen of which Sauron had a direct hand in creating. The greatest three Rings Celebrimbor crafted alone. Many other lesser rings were made, described in the The Silmarillion and by Gandalf, though they were generally considered as having been mere essays in the craft; practice, as it were, for the smiths. Sauron, however, planned to use the Rings to dominate the remaining Elves of Middle-earth. In accordance with this, he secretly forged the One Ring in the fires of Orodruin, seeking to bring all the rings and their wearers under his sway. However, when Sauron put the Ruling Ring on his finger, the Elves were immediately aware of him and took off their Rings. Furious at this turn of events, Sauron came against the Elves with open war and demanded that the Rings be given to him. Fortunately for the Elves, they were able to hide the greatest Three, but Sauron recovered the other sixteen. These he then gave to mortals; to Dwarves and Men. Seven he gave to Dwarves, but Nine he gave to Men, knowing that they would most easily bend to his will.