 Leslie was created Lord Balgonie and Earl of Leven in 1641, and finally retired in 1654.He carried out further improvement of his home, adding a two-storey building at the south-east corner of the courtyard.The initials FSAL and DAR, for Field Marshal Sir Alexander Leslie, and his wife Dame Agnes Renton, were found inscribed within the south-east block, suggesting that this was built prior to Leslie's elevation to the peerage.