LONDON • Ms Arlene Foster was just eight years old when her policeman father was shot in the head by Irish Republican Army (IRA) paramilitaries at their farmhouse near the then highly militarised border with the Republic of Ireland.
At 16, her school bus was blown up in another attack by the IRA.
Now aged 46, she holds the balance of power in British politics despite being dismissed as a has-been just a few months ago because of an ongoing scandal over a government scheme for renewable energy.
Mrs May is counting on Ms Foster's Democratic Unionist Party (DUP), with 10 MPs, to support her Conservative government which lost its majority in last Thursday's shock general election. The deal will give the DUP unprecedented access to power, including on the international stage through Britain's policy on leaving the European Union.
Ms Foster and her party are wading into uncharted territory, but the former solicitor and veteran Northern Ireland assembly member is well-versed in tough negotiations and is no stranger to adversity.
In an interview with The Belfast Telegraph, she admitted that the attacks she witnessed in her childhood had shaped her outlook on life.
"It is part of who I am and can't be denied. It informed my teenage years, it informed my political decisions, but at the same time I don't think we should let the past define what we do in the future," she said.
Her father John Kelly survived the 1979 attack, but it forced the family to move to the relative security of the nearby town of Lisnaskea.
She graduated from Queen's University in Belfast with a law degree. During her time there, she had joined the Young Unionist Association, the youth wing of the Ulster Unionist Party (UUP), which had ruled Northern Ireland virtually unchallenged since the state was created in 1922. While practising as a lawyer, she met her husband Brian. They have three children.
Ms Foster was elected to the newly-formed local assembly in 2003 but defected the following year to the rival DUP in protest over the terms of the Good Friday Agreement negotiated by the UUP. The accord ended 30 years of sectarian conflict in Northern Ireland.
She quickly rose through the DUP's ranks and became its leader in December 2015.