Pope Pius X, whose feast we celebrate today, lived from 2 June 1835 to 20 August 1914, and was Pope from 1903 onwards. He was the first pope since Pope Pius V to be canonized.
Pope St Piux X is much enamoured by traditionalists for his tough stance against modernism, promotion of traditional devotional practices and Gregorian chant, promotion of Thomism, and authored an excellent catechism. One of his most important reforms was to publish the first consolidated Code of Canon Law.
Some of his pastoral decisions however are of perhaps more debatable value: he reformed the Roman Breviary, taking it away from its previous alignment with the Benedictine; and encouraged First Communion before Confirmation, reversing the traditional order of reception of the sacraments.
A reluctant starter as Pope (the winner of the first result of the conclave was vetoed by the Emperor Franz Joseph), St Piux X had a strong Marian devotion, was considered by some to be too outspoken in his direct style and condemnations.
His charity was noteworthy: he filled the Apostolic Palace with refugees from the 1908 Messina earthquake; rejected any kind of favours for his family; his brother remained a postal clerk, his favourite nephew stayed on as village priest, and his three sisters lived together close to poverty in Rome; and often referred to his own humble origins, taking up the causes of poor people. "I was born poor, I have lived poor, and I wish to die poor."
Pope Benedict XVI gave a recent General Audience on his saintly predecessor, and its well worth a read.