Collection Manuscript/Mixed Material Image 1 of Item 43. Letter from the Yang Di Pertuan Muda of Riau to Colonel William Farquhar. Resident of Singapore. Written at Penyengat. 8 Syawal 1238 (18 June 1823). Item 43. Letter from the Yang Di Pertuan Muda of Riau to Colonel William Farquhar. Resident of Singapore. Written at Penyengat. 8 Syawal 1238 (18 June 1823).