sivertsen had during this period maintained close connections with the dutch republic, his son sivert was raised there. in this period he changed his name to "adelaer" ("adelaar"), dutch for "eagle". his son sivert adelaer served as a cadet on the ship of the famous dutch vice-admiral michiel de ruyter. retiring from venetian service he worked from 1661 till 1663 for an amsterdam merchant house, having a supply contract with the admiralty of amsterdam, one of the five dutch admiralties. in 1665, when the second anglo-dutch war threatened, he was offered a position in the dutch navy as a vice-admiral, but the refused. he started a salt-company together with william davidson of curriehill and jonas trellond in denmark. after the death of the dutch supreme commander lieutenant-admiral jacob van wassenaer obdam in the battle of lowestoft adelaer was considered for this function but again indicated that he had no interest in it.