Frederik Hendrik (Frederick Henry) was the only child of William of Orange and his fourth wife Louise de Coligny. His father was murdered a few months after his birth, and his half-brother Maurits (Maurice) – seventeen years older than Frederik Hendrik – succeeded him as stadtholder. Since Maurits had no legal heirs, Frederik Hendrik succeeded him in 1625. Maurits did however demand that Frederik Hendrik – who was 41 years of age by then – marry without delay, in order to safeguard the dynasty. In haste, Frederik Hendrik married Amalia of Solms-Braunfels, who was eighteen years his junior.
Frederik Hendrik, like his brother Maurits, enjoyed great success as head of the Dutch army. Under his leadership, many Dutch towns and cities were seized from the Spanish, earning him the nickname ‘Conqueror of Cities’.