The history of Irish theatre begins with the expansion of the English administration in Dublin during the early 17th century, and since then, Ireland has significantly contributed to English drama. In its early history, theatrical productions in Ireland tended to serve political purposes, but as more theatres opened and the popular audience grew, a more diverse range of entertainments were staged. Many Dublin-based theatres developed links with their London equivalents, and British productions frequently found their way to the Irish stage. However, most Irish playwrights went abroad to establish themselves. In the 18th century, Oliver Goldsmith and Richard Brinsley Sheridan were two of the most successful playwrights on the London stage at that time. At the beginning of the 20th century, theatre companies dedicated to the staging of Irish plays and the development of writers, directors and performers began to emerge, which allowed many Irish playwrights to learn their trade and establish their reputations in Ireland rather than in Britain or the United States. Following in the tradition of acclaimed practitioners, principally Oscar Wilde, Literature Nobel Prize laureates George Bernard Shaw (1925) and Samuel Beckett (1969), playwrights such as Seán O'Casey, Brian Friel, Sebastian Barry, Brendan Behan, Conor McPherson and Billy Roche have gained popular success. Other Irish playwrights of the 20th century include Denis Johnston, Thomas Kilroy, Tom Murphy, Hugh Leonard, Frank McGuinness, and John B. Keane.