The region which was once Oudh is a fertile portion of Northern India located in the contemporary province of Uttar Pradesh. The name is an anglicisation of the name “Awadh” which in turn is derived from the older name “Ayodhya,” the quasi-mythical capital city of Lord Rama (eponymous hero of the Ramayana). During the age of the Mughals, Awadh was an important province run by different Nawabs (governors) on behalf of the Mughal emperor. In the 18th century, the authority of the Mughals waned and the position of Nawab became a hereditary feudal one. The Nawabs of Awadh were a Persian Shia Muslim dynasty from Nishapur and they were renowned for their wealth and culture, however their (real) power was short-lived. In the latter half of the 18th century, the East India Company manipulated Oudh into serving as a buffer state against the Mughals and a de-facto treasury for their projects and adventures in northern India.
In 1819 the East India Company granted the Nawabs of Oudh permission to rule as independent kings. Anyone interested in power should immediately be able to spot the problem with that sentence: real authority was in the hands of the East India Company. However the delighted new king had a royal crown created for himself (designed by a British artist, Robert Home who painted portraits in the various courts of India). Here then is the crown of Oudh. Although it was a real object made of actual gold and jewels (unlike say, the Dutch crown, made of foil and fish paste) the crown of Oudh was a British stage prop meant to further disconnect Oudh from the last of the Mughals. By 1856, these theatrical machinations became too much for the British, and they dispensed with the Nawabs in order to rule the region directly. Yet the stagecraft of politics are a funny business—by annexing Oudh outright instead of running it through decadent puppet kings, the British precipitated the Indian Rebellion of 1857 (A.K.A. the First Indian War of Independence).