who were the rulers here?
The Delhi Sultanate.
Uttar Pradesh
Parts or all of Uttar Pradesh were ruled by the Delhi Sultanate for 320 years (1206–1526). Five dynasties ruled over the Delhi Sultanate sequentially: 
which indian state shares its border with the most number of states in india Uttar Pradesh when did this state came into existence? It was created on 1 April 1937 as the United Provinces of Agra and Oudh during British rule, and was renamed "Uttar Pradesh" in 1950.
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Uttar Pradesh [SEP] Delhi Sultanate
Parts or all of Uttar Pradesh were ruled by the Delhi Sultanate for 320 years (1206–1526). Five dynasties ruled over the Delhi Sultanate sequentially: the Mamluk dynasty (1206–90), the Khalji dynasty (1290–1320), the Tughlaq dynasty (1320–1414), the Sayyid dynasty (1414–51), and the Lodi dynasty (1451–1526).