The kroon was the official currency of Estonia from 1928 to 1940 and from 1992 to 2011. The official currency symbol: kr.  The kroon was pegged to the Swedish krona at par in 1924. The Bank of Estonia exchanged kroon for foreign currencies to ensure the kroon’s reputation. These actions helped restore confidence in the domestic banking and monetary system, assisting in the country’s economic recovery and improving the Estonian state’s worldwide reputation.

The first kroon was introduced in 1928, replacing the mark. Then, the Eesti Pank (Bank of Estonia) introduced banknotes in denominations of 10 krooni followed by 5 and 50 krooni in 1929, 20 krooni in 1932 and 100 krooni in 1935. Finally, the second kroon was reintroduced in 1992, replacing the Soviet ruble. After that, banknotes were issued in denominations of 1, 2, 5, 10, 25, 100 and 500 krooni, followed by the 50 krooni two years later.

The euro replaced the krone as the national currency of Estonia on January 1, 2011. The krone circulated together with the euro until January 15, 2011; after this date, it lost its status as legal tender. The Eesti Pank banknotes and coins of crowns for euros indefinitely.

The 100 Estonian krooni note front design features the portrait of Lydia Emilie Florence Jannsen (1843 – 1886), known by her pen name Lydia Koidula, was an Estonian poetess, playwright and one of the major figures of the national awakening movement in the 19th century. She was the founder of Estonian drama and theatre and took part in organizing the first Song Festival in 1869; the portrait is followed by a singing nightingale that represents Koidula’s most important collection of verses: “Emajõe Ööbik” (The Nightingale of the Emajõgi River). The design is completed with the Eesti Pank (Bank of Estonia) logo.

The reverse of the note Illustrates a storm in which waves hit the limestone cliff (Baltic Klint), which is the national stone of Estonia. The lettering of the note is presented in the Estonian language. This note is part of the 1991 – 1992 series, and its color is black and deep blue on light blue on a multicolor underprint.