Around 1746 Robert Rochfort 1st Earl of Belvedere (age 37) heard that his wife was being unfaithful with his brother Arthur. He locked her up at his house for the remaining thirty-one years of his life. He took his his brother Arthur to court for criminal conversation and was awarded the then huge sum of £2,000 in damages. Arthur, unable to pay, fled the country, but on his return to Ireland, he was thrown into Browne's Castle, (used as Dublin's debtors' prison at that time, and famous for being "the worst prison in the country",) where he died.

On 23 Aug 1746, Saturday, Robert Rochfort 1st Earl of Belvedere (age 38) and Richard Herbert (age 42) engaged in a duel over a long-standing debt of honour at the fields between Tottenham Court Road and Marylebone. Robert Rochfort 1st Earl of Belvedere (age 38) was badly wounded. Richard Herbert (age 42) received a ball in the eye which came out at the back of the skull. He survived albeit with mentaal impairment.