Jupiter-Saturn conjunctins occur roughly every 20 years and set the socio-politico atmosphere for the 20 years following the conjunction.

There appears to be a pattern of these conjunctions occuring in a certain element roughly every 200 years.

1600 to 1800 AD was dominated by the conjunctions occurring in FIRE signs.

1800-2000 AD was dominated by the conjunctions occurring in EARTH signs. .

2000 to 2200 AD will be dominated by the conjunctions occurring in AIR signs.
(Note: periods are rounded off).

This is important because these two slowest visible heavyweight planets set the mood for two centuries at a time, at least in this epoch.

The 1600's and 1700's was a time of exploration and adventure(Sagittarius), as well as war and new beginnings(Aries), and kingdom or rulership(Leo).

The 1800's and 1900's was a time of land and wealth aquisition(Taurus), as well as toil and hard work(Virgo), and defining national borders and laws and creating industry(Capricorn).

The 2000's and 2100's will be a time of great knowledge and communication(Gemini), as well as cooperation and justice(Libra), and freedom and truth(Aquarius).

Below are more specific times for these Jupiter/Saturn conjunctions and what signs they fall in. They were taken(most of them) from a book called Tables of Planetary Phenomena by Neil F. Michelson, 2nd edition. It details the date and time(UT) of the exact Jupiter-Saturn conjunction.