Rotterdam 1945 was written at the request of Maestro Arjan Tien, the chief conductor of the Marine Band of the Royal Netherlands Navy, to commemorate their 75th anniversary in 2020. 1945 also marked the end of World War II, the year that Johan's home country Holland was liberated from Nazi Germany. Johan's father was born in Rotterdam in 1910, so he has a special bond with this dynamic city. The composer used the numbers 1-9-4-5 to create the main theme and translated in into a four note motif: C - D' - F - G.