Uranus conjuncts Neptune only every 171 years (1136, 1307, 1478, 1649,1821, 1992), so we shouldn't have too much confusion about signs here. The conjunction regresses about 16 degrees through the zodiac with each occurrence (1992, 19 Capricorn; 1891, 3 Capricorn; 111 AD, 21 Cancer, 60BC [12 cycles from 1992] 5 Cancer)....
12x16=192: 289 (19 Capricorn) -192=97 (7 Cancer)
With the 1478 conjunction the Age of Discovery begins...the conjunction takes place in Sagittarius (expansion, foreign lands --Bartolomeo Diaz, Christopher Columbus); in early Capricorn in 1821, the Industrial Revolution comes along and changes the structure of civilization; in 1992, the Computer Age kicks in, with its very deep changes in our technological and social fabric. Seen in this way, Uranus and Neptune are Collective planets; they depict the social background in which anyone born during the period will necessarily operate. And of course, each of these planets also has very noticeable effects on the individual apart from its collective-generational meaning. Society as a whole is an organism, and each individual is an organism. The effects of planets are seen at each organic level.
The first conjunction of these two planets in the present Great Cycle of Uranus-Neptune occurred on 26 March 919 BC in the 9th Degree of Aries. Jupiter, Uranus, Mercury and Neptune were clustered between 6 and 9 Aries. The next Great Cycle will begin in 2681, when the two planets meet in the Last Degree of Pisces (less than 15' from the cusp of Aries).
Notice that the first conjunction in the present Great Cycle corresponds roughly with the emergence of "Civilization"...this is a 3500-year evolutionary cycle. The use of iron, the introduction of the wheel, the beginnings of astronomy and land surveying (with the concomitant development of mathematics), writing, the development of stratified societies, etc., all began in the period around 1000 BC more or less independently in the valleys of the Yangtse, the Indus, the Euphrates.