Why was Tsar Peter unable to hide his identity?

Explanation:

Born on May 30, 1672, Peter was named Peter Alexowitz, meaning 'Peter the son of Alexis'. His father, Tsar  Alexis, had married twice, and Peter was the first child of his second marriage. There were already six  daughters and two rather unhealthy sons, named Feodor and Ivan, from the first marriage. When Alexis  died very suddenly in 1676, Feodor ruled until his own death in 1682, when the ten-year-old Peter became  Tsar jointly with his half-brother Ivan. It was not until 1696 that Peter began to rule alone.