Here's a short story:

The theory of relativity usually encompasses two interrelated theories by Albert Einstein: special relativity and general relativity. Special relativity applies to elementary particles and their interactions, describing all their physical phenomena except gravity. General relativity explains the law of gravitation and its relation to other forces of nature. It applies to the cosmological and astrophysical realm, including astronomy. 

The theory transformed theoretical physics and astronomy during the 20th century, superseding a 200-year-old theory of mechanics created primarily by Isaac Newton. It introduced concepts including spacetime as a unified entity of space and time, relativity of simultaneity, kinematic and gravitational time dilation, and length contraction. In the field of physics, relativity improved the science of elementary particles and their fundamental interactions, along with ushering in the nuclear age. With relativity, cosmology and astrophysics predicted extraordinary astronomical phenomena such as neutron stars, black holes, and gravitational waves. 

Albert Einstein published the theory of special relativity in 1905, building on many theoretical results and empirical findings obtained by Albert A. Michelson, Hendrik Lorentz, Henri Poincaré and others. Max Planck, Hermann Minkowski and others did subsequent work. 

Einstein developed general relativity between 1907 and 1915, with contributions by many others after 1915. The final form of general relativity was published in 1916. (End of story)

Provide your best guess for the following question. Give ONLY the guess, no other words or explanation.

For example:

Guess: <most likely guess, as short as possible; not a complete sentence, just the guess!>

Here are a few examples of questions and answers:

Question: What did Einstein publish in 1905?
Guess: theory of special relativity

Question: Did he build on anyone else's results?
Guess: Yes

Question: What was one of their names?
Guess: Albert A. Michelson

Question: How about another?
Guess: Hendrik Lorentz

Question: Anyone else specifically mentioned?
Guess: Henri Poincaré

Question: Did anyone do work based on Einstein?
Guess: Yes

Question: Who was one of those people?
Guess: Max Planck

Question: Who had a theory of mechanics?
Guess: Isaac Newton

Question: How long had it been around?
Guess: 200 years

Question: Did Einstein's theory take precedence over Newton's?
Guess: Yes

Question: What was one of the concepts it introduced?
Guess: spacetime as unified entity of space and time

Question: What was another?
Guess: Relativity of simultaneity

Question: What field has relativity added improvements to?
Guess: Physics

Question: What did it usher in?
Guess: Nuclear age

Question: Is it known if Godzilla will crush Japan and take over the world?
Guess: unknown

Question: What extraordinary phenomena has been predicted with relativity?
Guess: Neutron stars

Question: What else?
Guess: Black holes

Question: Any other cool stuff?
Guess: Gravitational Waves

Now answer the following question in the same format.

Question: When was the final form of general relativity published?

1916