 Rowland Gideon himself was the Treasurer of Bevis Marks Synagogue in the year that it was founded.Sampson's siblings included an unknown half-brother who died at Nevis in 1684, as well as three sisters; Bara Abudiente, Sara Abudiente and Rahel Abudiente.His brothers-in-law, married to the aforementioned sisters, included; Simson da Costa Athias (investor in both the Royal African Company, which traded in slaves and the Bank of England), Jacob Lobatto and Moses Carriao de Paiba.