Resumen: First of all, we need to understand why there are other geometries such as Hyperbolic geometry besides the intuitive Euclidean geometry. Who discovered this geometry? Lobachevski, a young scientist who decided to leave the medical career to devote himself completely to the study of a geometry that he called “imaginary geometry”, is a founder of this geometry. He made progress not only in mathematics but also in physics, such as Einstein’s theory of relativity. How did Lobachevski come up with this geometry? Before giving an answer to this question, let’s see what an axiomatic system is.