J. T. Grein (1862–1935), a Dutch-born theatre impresario and drama critic
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Grein, Austria, a municipality in the district Perg in Upper Austria
In 1895, Grein invited Aurélien Lugné-Poe to present a season of productions in French, of Ibsen's Rosmersholm, The Master Builder and Maurice Maeterlinck's symbolist L'Intruse and Pelléas and Mélisande.
The influences were not all one way: in April 1907, Grein organised a visit by Herbert Beerbohm Tree's company – based at His Majesty's Theatre – to Hanover and Berlin.