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What is the most important theorem in complex analysis?

The following is taken from a very beautiful book which I bought 2 months back.
（Differential Geometry in Physics(Gabriel Lugo - 2021)）

    In June 1979, an international symposium on differential geometry was held at the Berkeley campus in honor of the retirement of Professor S.S. Chern. The invited speakers included an impressive list of the most famous differential geometers of the time. At the end of the symposium, Chern walked on the stage of the packed Auditorium to give thanks and to answer some questions. After a few remarks, a member of the audience asked Chern what he thought was the most important theorem in differential geometry. Without any hesitation he answered, “there is only one theorem in differential geometry, and that is Stokes’ theorem.” This was followed immediately by a question about the most important theorem in analysis. Chern gave the same answer: “there is only one theorem in analysis, Stokes’ theorem”. A third person then asked Chern what was the most important theorem in complex variables. To the amusement of the crowd, Chern responded, “There is only one theorem in complex variables, and that that is Cauchy's theorem. But if one assumes the derivative of the function is continuous, then this is just Stokes’ theorem”.

    Now, of course, it is well known that Goursat proved that the hypothesis of continuity of the derivative is automatically satisfied when the function is holomorphic. But the genius of Chern was always his uncanny ability to extract the essential of what makes things work, in the simplest terms.

Now people of mathematics need no introduction of Professor S.S.Chern. He was one of the finest minds in differential geometry of the 20th century.
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