Generate a realistic image of Lionel Messi, the world-renowned soccer player, sitting atop a majestic brown horse, with the sprawling green field and grand mansion from the 1960s in the background. The horse should have four legs and a sturdy body, with its mane flowing in the wind. Messi should be seated comfortably on a saddle, wearing casual clothing and a smile on his face as he takes in the tranquil surroundings. The image should be well-balanced, with no floating heads or additional limbs.