Colonel Robert Duckenfield (c.1619-1689) was the Parliamentary commander who received the surrender of the Isle of Man in 1651. After William Christian (Illiam Dhone) led the Manx people in rising against the Stanley garrison, Duckenfield crossed from Lancashire to take possession of the Island. Charlotte de la Trémouille held out briefly in Castle Rushen and Peel Castle before negotiating terms. Duckenfield's arrival marked the end of direct Stanley rule and the beginning of the Interregnum on the Island.

The Countess tried to trade the Island for her husband's life. The Earl had written to her from prison advising her to comply, and on receiving the letter she thought it prudent to do so, sending her servant Broyden with letters to Duckenfield, the Commander in Chief appointed for the expedition against the Island, treating about its rendition on condition that the Earl might be released. It was too late. The Earl had been beheaded some days before the letter reached her.

His chaplain was used on the Earl as well. Mr Slater, Duckenfield's chaplain, came to him from the Governor to persuade him that his life was in no danger, and the Earl heard the discourse patiently but did not believe a word of it, being resolved not to be deceived.

He reported to London on the spoils. John Bradshaw wrote to him in 1651 acknowledging his letter of 3 December with papers enclosed concerning the goods in the Isle of Man likely to be prize, and noting that this and his other letters since the taking of the place had been referred on.