In about 326 b.C. Alexander the Great reached India after having created the mightiest empire to date. He had built that empire based in his will and determination together with the support of his military commanders in less than10 years since he succeeded his dad as King of Macedon.
After having overstretched his resources and capabilities beyond any conceivable limit, he had to face that India was too much, too complex, to far away, too powerful per se.
Alex did not realize this, and in fact he launched the invasion.
But his up-to-then-loyal commanders understood better their own limitations in front of India, and made their own U-turn and headed home.
This lack of support forced Alex to head back too… and in less than three years, he was actually dead.
His generals ripped the Empire, split is into fiefs and Macedon’s ruling on the mightiest empire on earth was over for ever.