There are multiple origins and translations for the name Ivan:
1. East Slavic (Russian Иван) & Spanish (Iván) hugely popular form of the name John (Iohannes) which actually means - "God (Ya/Jehovah) is merciful (Hanan)".
2. Derived from the Slavic word ива [iva] - "willow". Willow has had many symbols in in ancient times.
Ivan the Terrible (25 August 1530 - 28 March 1584) was Grand Prince of Moscow from 1533 until his death. His long reign saw the conquest of the Khanates of Kazan, Astrakhan, and Siberia, transforming Russia into a multi-ethnic and multi-confessional state spanning almost one billion acres. Ivan managed countless changes in the progression from a medieval state to an empire and emerging regional power, and became the first ruler to be crowned as Tsar of all Russia.