LONDON — The centenary of the birth of Alan Turing, the World War II code-breaker and father of modern computing, was being marked on Saturday with memorials, exhibitions and academic gatherings in his native Britain and beyond.

Google honored him for the day with an online puzzle to commemorate his Turing Machine, which provided the basis of much of modern computing.

“His essential insights into mathematics and the nature of computability dealt with the limits of what can be calculated by machines,” The New York Times wrote in an editorial recording his legacy.

The anniversary was also marked by renewed efforts to gain a pardon for the mathematical genius, who died by poison at the age of 41 after being hounded by an ungrateful establishment on account of his homosexuality.