The Khedivate of Egypt and Sudan lasted from 1844 until 1914. The term refers to khedive, the title assumed by Muhammad Ali Pasha, a leader of Egypt and Sudan during the Ottoman Empire. The term khedive is roughly translatable as viceroy, which, presumptuous or not, was certainly a step up from the former term, which meant “governor”.
Fortunately for Pasha, the term khedive was officially recognized by the Ottomans in 1867, and the title was used by the region’s leaders (including Ismail Pasha) until 1914.
A popular philatelic collectible from the time that Egypt (and Sudan) was a khedivate is the interpostal seal, a round piece that is often for sale to collectors in a wide variety of forms. The seals were used on letters or packets of letters between two post offices, with the originating office indicated on the seal. These are common and there are many hundreds of variations.
See also: Egypt rare stamps for philatelists and other buyers
In addition to these seals, regular stamps were issued by Ismail Pasha starting in 1866. Khedivate stamps are somewhat less common than the interpostal seals, but some fantastic examples can be added to any collection with a little luck and patience (the two watchwords of all stamp collecting!).