Friedrich Engels ( ENG-gəlz; German: [ˈfʁiːdʁɪç ˈʔɛŋl̩s]; 28 November 1820 – 5 August 1895) was a German philosopher, political theorist, historian, journalist, and revolutionary socialist. He was also a businessman and Karl Marx's lifelong friend and closest collaborator, serving as a leading authority on Marxism.