1940 - 1950

1940-41 - From 10 June to 31 March emigrates via southern France, Spain, and Portugal to the USA. Most manuscripts remain in France: Martinu takes with him only four scores. In June Vitezslava Kapralova dies. While fleeing Martinu writes the Sinfonietta giocosa for piano and small orchestra. Settles in New York. Composes the Concerto da camera for violin and chamber orchestra. On 14 December scores a major success with the premiere of his Concerto grosso by the Boston Symphony Orchestra under Serge Koussevitzky.

1942 - Composes the Symphony No. 1, premiered in November again by Koussevitzky. Writes another symphony in each succeeding year through 1946. Their premieres and frequent performances confirm Martinu's important standing in musical life in the USA. In the summer accepts an invitation from Koussevitzky to teach in the summer courses at the Berkshire Music Center. (Later he will teach at the Mannes School of Music in New York and at Princeton University.)

1943 - Composes the Concerto for Two Pianos and Orchestra, the Concerto for Violin and Orchestra No. 2 for Misha Elman, and the orchestral Pamatnik Lidicim (Memorial to Lidice).

1944 - Composes the Symphony No. 3 and the Sonata for Violin and Piano No. 3. On 6 June the allies land in Normandy. Beginning of a relationship of many years (until 1954) with Rosalie Barstow.
1945 - Celebrates the end of the Second World War by composing the Rhapsodie Tcheque for violin and piano. Learns of the death in March 1944 of his mother and the death in July 1945 of his close friend Stanislav Novak. Follows in shock the political trial of Vaclav Talich.

1946 - Again teaches at the Berkshire Music School, where on 17 July he suffers a severe injury whose consequences (mainly a serious hearing defect, dizziness, and headaches) he will feel for the rest of his life. Composes the Toccata e due canzoni for Paul Sacher and his Basel Chamber Orchestra.

1947 - Beginning of the 'Cold War'. Martinu composes Three Madrigals for Violin and Viola.

1948 - In February the communist coup in Czechoslovakia. On the day of the tragic death of Jan Masaryk, 10 March, Martinu completes his Piano Concerto No. 3. Abandons the idea of returning to Czechoslovakia and remains in exile. In the summer his first sojourn in Europe (in France and Switzerland) since his arrival in America in 1941. Named a professor of composition at Princeton University in New Jersey starting in September; he will remain there until 1951.

1949 – Composes the Sinfonia Concertante for two violins, violoncello, oboe, bassoon, and small orchestra for Paul Sacher.

1950 - Beginning of the Korean crisis. Martinu composes the Sinfonietta La Jolla for chamber orchestra.