Thank you for the opportunity to help you with your question!
If you mean "religious beliefs" - he was an atheist. Karl Marx invented Communism. However, he did not invent Leninism or Stalinism or any other "Communist" ideology that has been put to practice. Real Marxism has never been put to practice. The Bolshevik Revolution led by Lenin happened in 1917. Marx even specifically pointed out that Russia was unable to create a real revolution. Lenin took a shortcut in the process of a Communist state. According to Marx, it would happen on its own and it was an inevitable idea
Please let me know if you need any clarification. I'm always happy to answer your questions.