After the war, however, the intelligence contributions of black Americans began to be lost to history. While racial prejudice probably played a part in this, as it did regarding the military contributions of black American Union military units, several other factors added to this lack of recognition. Historically, most successful spies do not want their identities made public. Even individuals who may have provided one-time pieces of useful intelligence usually prefer anonymity. This was particularly true in the emotional period after the Civil War, when many of these black Americans lived near people who had not given up their insurgency and were intent on imposing white supremacy on blacks.