Well typically, circumcision was a very common practice in certain religions such as Judaism and Islam. It is considered to be an extremely important practice for males to be circumcised.

Circumcision was more know to be a religious practice for many Jewish men and so the nazi's used one's circumcision status to determine if one was Jewish or not. If they were, then they were sent off to a concentration camp. The article below explains more about it.

Solomon was more than well aware that if any of the soliders had found put he was Jewish, then it would be very likely that he would be sent a concentration camp.

[history of male circumcision] ](https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.tandfonline.com/doi/pdf/10.1016/S0968-8080(07)29303-6&ved=2ahUKEwiDlMGHwLHsAhWewjgGHbEWCY0QFjAAegQIBBAB&usg=AOvVaw2kLgoOXAl8vqLnUEwi638Y)