Maria Theresa's father was born in 1740.
Maria Theresa Walburga Amalia Christina ( Maria Theresia [ maˈʁiːa teˈʁeːzi̯a ] 13 May 1717 -- 29 November 1780 ) was the only female ruler of the Habsburg dominions and the last of the House of Habsburg . She started her 40-year reign when her father , Emperor Charles VI , died in October 1740 .