A Zeppelin is a type of rigid airship named after the German inventor Ferdinand von Zeppelin (German pronunciation: [ˈt͡sɛpəliːn] ) who pioneered rigid airship development at the beginning of the 20th century. Zeppelin's notions were first formulated in 1874 and developed in detail in 1893. They were patented in Germany in 1895 and in the United States in 1899.