Early life. Ivan was the second son of Ivan the Terrible by his first wife Anastasia Romanovna.His brother was Feodor.The young Ivan accompanied his father during the Massacre of Novgorod at the age of 15. For five weeks, he and his father would watch the Oprichniks with enthusiasm and retire to church for prayer. At age 27, Ivan was at least as well read as his father, and in his free time …
https://en.wikipedia.org/wiki/Tsarevich_Ivan_Ivanovich_of_Russia

