Although the fact that kings fathered illegitimate sons was taken for granted, other facts indicate that Sverre was in his early thirties when he came to Norway, such as the age of his own sons and nephews.
Meskipun fakta bahwa raja-raja yang menjadi anak laki-laki yang tidak sah dianggap remeh, fakta lain menunjukkan bahwa Sverre berusia awal tiga puluhan ketika datang ke Norwegia, seperti usia anak-anaknya dan keponakannya sendiri.