Robert Walker (after) ( 1599 - 1658 ) was a painter. Robert Walker (after) s works have been put up for auction numerous times, with realized prices surpassing estimated prices, varying from 607.97 USD for Portrait of a gentleman, bust-length, in armour and a lawn collar, feigned oval in 2005 to 7001.19 USD for PORTRAIT OF OLIVER CROMWELL (1599-1658), LORD PROTECTOR OF ENGLAND in 2015 , based on