John Of Gaunt, 1st Duke of Lancaster was a member of the Royal Dynasty of Henry Grosmont. Henry was the Earl of Lancaster. When Henry died the title of Duke of Lancaster was given to John of Gaunt.

John of Gaunt lived in Halton Castle for much of his life as the Duke of Lancaster, but retired to Leiceter Castle and died there.

the simplest answer is that the familys of the houses of York and Lancaster

were cousins and their common ancester was the Plantagenet King, Edward the III, and John of Gaunt the Duke of Lancaster

Lancaster John O' Gaunt Rowing Club was created in 1842.

It's John. John of Gaunt. In a crossword puzzle, the answer would be "JOHNOF."