It was any girl’s dream: young Molly Allgood, just 19 years old, an assistant at Switzer’s drapery, was about to make her debut on the Abbey stage. As she waited nervously in the wings, the stage manager called out, “beginners please”. And Molly dissolved in tears.

It was the conventional call for the actors to be ready, but Molly had never heard it before; she took it to be a jibe at her lack of experience.

But Molly impressed. Within a year, she was taking a lead role at the Abbey, in John Millington Synge’s ‘Riders to the Sea’, directed by the playwright. Synge was naturally shy, and had a reserve appropriate to his strict Puritan upbringing. But in the agreeable company of the Abbey players, he relaxed; an attraction grew between the writer and the young actress and, tentatively, a relationship. Synge initially sought to keep it private, fearing the hostility of his family and of his co-director at the Abbey, Lady Gregory.

“You must not mind if I seem a little distant at the Theatre,” he wrote to Molly. “Every one is watching us, and even when we are publicly engaged I do not care to let outsiders see anything.” (Synge’s letters have been edited in various volumes by Ann Saddlemyer.)

Diffident in public, he was furiously jealous in private. Molly was young, beautiful, and charismatic, fast becoming a star. She was surrounded by admirers and, it appears from his letters, perhaps not entirely disinclined to encourage them.

“For God’s sake,” he warned her, “keep clear of the men who dangle after actresses”. In another letter: “Of course you won’t go to Power’s dance, the thought would be ANGUISH to me!!”

On one occasion, after she had apparently stood him up, he wrote to her in an insomniac frenzy, at 4am: “I wish to God I had never been born.” On another, “I am almost frightened sometimes when I think how wildly I love you.”

Synge kept up a constant stream of love letters, with a frequency more suited to email: he often wrote to Molly just hours after they had parted, or sent her scraps of paper with notes written to her as updates during the same day, like an intimate blog. He called her “changling”, and signed off his letters, after the character in the play through which they first met, “your old Tramp”.

When he wrote in a temper, he often wrote again shortly after, apologising or explaining. “Don’t you know, changling, that I am an excitable, over-strung fool,” he wrote. “I am ashamed of my arid little letters when I have posted them, and of my foolish tempers, sometimes, when I bid you good-bye.”

It was a momentous time in Synge’s life, as it was in the Irish theatre. After a decade of incremental progress as a writer, ‘The Playboy of the Western World’ (with Molly playing the leading role of Pegeen Mike, which he had written for her) thrust him into the limelight in Ireland, and brought acclaim internationally.

The day after it opened, to near-riots, he wrote to Molly: “It is better any day to have the row we had last night, than to have your play fizzling out in half-hearted applause. Now we’ll be talked about. We’re an event in the history of the Irish stage.” He was a leader in a theatre that was at the vanguard of world drama. He was in love. And, though he didn’t know it, he was dying.

Synge had had his first operation ten years before, and had since suffered from repeated bouts of illness. Throughout 1907 and 1908, he and Molly planned for their wedding, but were thwarted by his ill health. In June 1907, he wrote that the doctor had advised him to “recover myself a bit before I get married”.

“It seems very hard to have to put off our wedding again, but it will only be I hope till the autumn or early winter.”

But they didn’t get married that autumn, or winter. In January 1908, he rented a flat in Rathmines, hoping to move Molly in once they were married. But in April, he fell very ill, and nearly died. He failed to regain his full health and, over the following months, he deteriorated.

By March 1909, he no longer had the energy to write, and had lost hope; Molly, in despair, tried to have a mass said for him, but was rebuffed by the priests she spoke to, for Synge was a Protestant.

On Wednesday March 24, one hundred years ago this week, John Millington Synge died. He was 37, and had been killed by the cancer, Hodgkin’s lymphoma. Molly maintained her career as a star of the Abbey, though she later married a theatre critic, which could be taken by some as an indication of misfortune.

In just six years, and six plays, Synge left an immense legacy, which is being celebrated in an exhibition of his manuscripts and photographs, just opened in the Long Room of Trinity College’s Library, and in Garry Hynes’s ongoing ‘DruidSynge’ project. (‘Playboy’ tours the UK in May and June, with some dates in Galway: see www.druid.ie.) He is a giant of the Irish theatre. He was also, though, the “old tramp” of a young girl called Molly. Therein lies the man that made the writer.

Written for my Irish Independent Saturday theatre column.