Sirius Black is born

Sirius is the first child of Orion and Walburga Black of number 12, Grimmauld Place in London. He is named after previous Sirius Blacks: the brother (1845-1853), and son (1877-1952) of his great-great grandfather, Phineas Nigellus.  The Black family is a pure-blood family with extreme elitist attitudes. Nearly the entire family was in Slytherin house at Hogwarts, Sirius being the notable exception.