Ron Guth: The first Five Dollar gold pieces minted in America were of the Draped Bust, Small Eagle type, which first appeared in 1795. These classic American gold coins bore no denomination anywhere on the coin; it's value was determined by its weight (as were all gold and silver coins of the time). Thus, when the price of gold went up, and the value of the coin exceeded it's decreed value of $5, the coins were melted. As a result, coins of this type are somewhat scarce today, simply because so many were destroyed in subsequent years. The Small Eagle type was minted from 1795 to 1797; in 1797, the reverse design was switched over to the Large Eagle (Heraldic Eagle) design. The lone 1798 Small Eagle variety was an unusual event where a reverse die of 1795 was resurrected, polished and used for a short run at a time when the Yellow Fever was creating havoc at the U.S. Mint.
All dates of this type are scarce and valuable; some individual die varieties are unique and/or prohibitively expensive. The 1798 Small Eagle reverse is one of the most desirable of all U.S. gold coins.
Interesting varieties include a 1795 with the final S of STATES punched over a D, and a 1796/5 overdate. Variations in the number of obverse stars relate to the number of states admitted to the Union, though the sequence in which they were used was not consistent.
High-grade, problem-free examples of this type are very rare, although some Choice to Gem examples are known.
Sources and/or recommended reading:
"Early U.S. Gold Coin Varieties" by John W. Dannreuther and Harry W. Bass, Jr.
"United States Half Eagle Gold Coins 1795 to 1834" by Robert W. Miller, Sr.
"Walter Breen's Complete Encyclopedia Of U.S. And Colonial Coins" by Walter Breen