(John), or HALIFAX, or Sacrobyco, was, according to Leland, Bale, and Pitts, born at Halifax in Yorkshire; according to Stainhurst, at Holywood near Dublin; and, according to Dempster and Mackenzie, in Nithsdale in Scotland. The last-mentioned author informs us, that, having finished his studies, he entered into orders, and was made a canon regular of the order of St Augustin in the famous monastery of Holywood in Nithsdale. The English biographers, on the contrary, tell us, that he was educated at Oxford. They all agree, however, in asserting that he spent most of his life at Paris; where, says Mackenzie, he was admitted a member of the university on the fifth of June in the year 1221, under the lyndics of the Scotch nation; and soon after elected professor of mathematics, which he taught for many years with applause. We are told by the same author, that he died in 1256, as appears from the inscription on his monument in the cloisters of the convent of St Maturine at Paris. Holywood was certainly the first mathematician of his time. He was contemporary with Roger Bacon, but probably older by about 20 years. He wrote, 1. De sphera mundi; often reprinted, and illustrated by various commentators. 2. De anni ratione, seu de computo ecclesiastico. 3. De algorithmo, printed with Comm. Petri Cirvilli Hilp. Paris 1493.