In the small hours of June 20, 1837, an eighteen-year-old princess was roused from sleep at Kensington Palace and told that she was now queen. Her uncle, King William IV, had died around two in the morning, and with no surviving legitimate children of his own, the crown passed to his niece, Alexandrina Victoria. By the time the sun was up, Britain had a new monarch, one whose name would come to define an entire age.

Victoria received the news in her dressing gown, coming down to meet the Archbishop of Canterbury and the Lord Chamberlain alone, a small but deliberate assertion of independence after a sheltered and tightly controlled upbringing. That same morning she held her first Privy Council meeting, and those present were struck by the composure of someone so young thrust so suddenly into the center of national life.

She was crowned the following year, on June 28, 1838, in Westminster Abbey. In 1840 she married her cousin, Prince Albert of Saxe-Coburg and Gotha, a love match as much as a dynastic one, and together they had nine children, whose marriages would eventually link Victoria to royal houses across Europe and earn her the nickname “the grandmother of Europe.”

Her reign lasted nearly sixty-four years, until her death in January 1901. It was a period of staggering change: industrial expansion, the spread of the railways, sweeping social reform, scientific upheaval, and the height of the British Empire, over which she presided as Empress of India from 1876. The era took her name, and “Victorian” still conjures a whole world of values, fashions, architecture, and contradictions.

For more than a century she held the record as Britain’s longest-reigning monarch, a distinction she kept until Queen Elizabeth II surpassed her in September 2015.

Not bad for a teenager woken before dawn with the news that her life, and her country, had just changed forever.