An Alternate timeline, known informally as an alternate, was the term used by Crosstime Traffic to describe the various timelines where they established business. An alternate timeline was a world where historical decisions and events had not gone the way they had in the home timeline.
Such alternates were exploited for their resources to feed the hungry, resource-scarce home timeline by the Crosstime Traffic. However, the company was always in the fear that one of the alternates were advanced enough to travel to different alternates and have trading enterprise and would be hostile toward competition.
Alternates with oppressive regimes or hard conditions, such as those destroyed by nuclear war, were helped by CT, though this wasn't always so. Fraternizing with someone from an alternate was discouraged, though an employee bringing a lover to the home timeline was not unknown.
Note: The first entry in each sub-section is the main setting of that novel. Most of the rest are just mentioned. However, in In High Places, the first two alternates listed are visited for large parts of the novel.
- Agrippan Rome, in which the Roman Empire never fell and continued to thrive throughout the 21st century.
- Vikings settled North America.
- Successors of Alexander the Great ruled a half dozen empires that stretched from Spain to the borders of China.
- Native Americans are the most advanced civilization as European civilization developed far later.
- The Spanish Armada conquered England in 1588 and Spain created an empire that bordered Russia in the 21st century.
- The Confederate States won the American Civil War and remained a nation in the 21st century.
- Nazi Germany won World War II.
- China discovered and settled the New World.
- The American Revolution never happened. North America was a contented part of the British Empire, which ruled three-quarters of the world.
- China kept European trade out of the Indian Ocean. However, it was subsequently conquered by Japanese warlords.
- Several alternates in which humans were still hunter-gatherers.
- Several alternates in which humans never evolved.
- Palestine remained a sleepy Turkish province.
- Nuclear weapons were never invented. The Soviet Union and the United States fought World War VI in the 2090s.
- In an alternate designated "3477," the German Empire won a brief World War I and went on to conquer the world.
- Europeans never discovered North America and Native Americans still had a Bronze Age level of technology.
- Humans began terraforming Mars by crashing ice asteroids into its surface to create oceans.
- The 14th-century Great Black Deaths took 80% of European lives, leaving Islam to dominate much of that continent. Christianity underwent a drastic change, and technology stagnated throughout the world.
- The Roman Republic lost the Samnite Wars, and technology remained in the Bronze Age. Neither Christianity nor Islam existed in that alternate.
- In an alternate with a low level of technology, Christianity seemingly never existed.
- The US Constitution was never adopted, and the United States dissolved in the early 19th century, leading to a North America shared by numerous small, often warring countries.
- Humans considered sending manned missions to Venus.
- The U.S. was a tyrannical state which dominated the world.
- Human life never evolved, so Crosstime set up quarantine safehouses in this alternate, where species such as the Carolina Parakeet and the passenger pigeon flourished.
- The Soviet Union won the Cold War.
- Several alternates where Fascism came to dominate the world, including one in which the Axis conquered the United States.
- The Russian-American War was fought with atomic bombs in 1967 and left the world in ruins.
- Other alternates where the last war was started by the United States, China, and even Nazi Germany.