Sir Peter Hall's repertory season of classics and new plays at the Old Vic has come into its own this month with two of the most rewarding productions in London: one of each, in fact. The classic is The Seagull (reviewed last week). The new play is Sebastian Barry's Prayers of Sherkin. First performed at Dublin's Abbey Theatre in 1990, Prayers of Sherkin is one of a series of plays in which Barry, who wrote the award-winning Steward of Christendom, uncovers the forgotten lives of some of his ancestors. These people - real people, as it were - whose lives have been re-imagined by Barry, are way outside the usual run of stage characters. Through them Barry leads us into Ireland's history by the back door. A story set in the 1890s about a chandler and his daughter, Prayers of Sherkin feels as if it has been crafted with the same unhurried care with which we see the chandler build up his candles by pouring on layers of hot wax. By the end, in John Dove's scrupulous production, it glows with the same modest light.

Fanny Hawke, the bright, ungainly heroine, is beautifully caught by Catherine Cusack, whom you half expect to see brandishing a lacrosse stick. She lives on Sherkin, off the west coast of Ireland, which, as her aunt tells a newcomer, is "not a holiday island". Home is a place when plainness is spoken of in the highest terms. Fanny's bed is the dining table.

On the mainland, Fanny meets a lithographer, Patrick Kirwin (the attractively earnest Stanley Townsend), but the Hawkes belong to a visionary sect that left Manchester in the 1790s under the inspiration of Matt Purdy, an artisan, played with transparent decency and fervour by Ron Cook. It is an article of faith that they cannot marry outside the sect.

In lesser hands, Prayers of Sherkin would show enlightenment triumphing over religious prejudice, but it is characteristic of Barry's sincerity that while Fanny does choose to marry Kirwin, she doesn't turn on her father or his faith. The sadness is unavoidable, but the inevitability of the split moves us because it is rooted in respect. Fanny's father, played with a superb mixture of authority and anxiety by Julian Glover, acknowledges that "ours is a bitter creed". When the two face each other after Fanny has made her decision, the scene is brief. And silent.

The designer, Anthony MacIlwaine, evokes the west coast with a spareness that matches the Shaker-style furniture. The richness is elsewhere: explicitly in the lyrical dialogue, and implicitly in the quality of the relationships, which has a rare gentleness. There are tender performances from (among others) Harry Towb as the stiff-collared, courteous owner of the mainland shop, and Susan Engel as the aunt who is losing her sight. The final moment, when Cusack is rowed from the island to the mainland, and one light goes down on her father and then another one comes up on her future husband, tells it perfectly.

For those of us unlikely to gain admission to an all-women's Turkish bath, Steaming, Nell Dunn's 1981 comedy, which returns to the West End with Jenny Eclair and Julie T Wallace, offers some welcome anthropological insight. Women who go to baths appear different from other people in one important respect. They speak in complete anecdotes. During an anecdote the other women there do something even stranger. They look directly at the speaker or stare out into the middle distance holding an expression of intense interest. In Turkish baths, it seems, people don't interrupt, half-listen, talk at the same time, or suddenly say something completely different to someone else entirely. For all Steaming's self-conscious bawdiness - seized on by Eclair with the practised relish of a stand-up - the conversation is conducted with a dutifulness that Mary Poppins would applaud.

This is just as well, as the denizens of the baths have a fair bit of autobiography to off-load. "At 15 I was ... " . "There was another man once ... ". "I saw William the other day. The first time since the divorce ... " With each gambit, the others clamp on the expression of intense interest and the speaker is off. It isn't easy as a member of the audience to be as good a listener. I tended to miss what people were saying when they took off their towels. Some of us can only concentrate on one revelation at a time.

After Dunn has introduced us to the various individual problems that make up the female experience (c 1980, ) she brings the group together to face one big problem: the closure of the baths. We return after the interval to find that Robin Don's splendid set, the one aspect of the production that really does deserve to to be in the West End, is covered with banners saying "Trigate Baths Must Stay Open". The slogans are written in very large capital letters. But then so is quite a lot of the evening.

One advantage of going to see Shakespeare in Romanian is that you don't miss a word of what is said. It is up there in the surtitles. In Titus Andronicus (Lyric, Hammersmith) one of the sons of the Queen of the Goths stumbles across some Horace, and a couple of lines pop up in luminous green. Three hours of murder, rape and mutilation and then Shakespeare hits us with Latin. I was hoping that the director, Silviu Purcarete - whose radical interpretation had already given us tribunes who broadcast their speeches on TV, a swirling back-projection, and a Titus who reclines on a trolley - might drop in a gadget that would provide some surtitles for the surtitles.

This National Theatre of Craiova production, which first opened in 1992 and has toured half the world, combines the full ghastliness and grotesqueness of Titus in an eerie, post-modern context of drifting chaos and cruelty. The almost naked, blubbery figures of Chiron (Tudorel Filimon) and Demetrius (Valer Dellakeza) who run round like Tweedledum and Tweedledee, are bound and gagged while Titus uses a foot pedal to sharpen his blade on a wheel.

What dominates is the visceral father-daughter relationship. Stefan Iordache gives a heavy-lidded, grizzled performance as Titus and Ozana Oancea is an achingly pale Lavinia. If this Titus doesn't have the formal visual splendour which characterised Les Danaides, seen at Birmingham last year, it has its own crazy brutal logic.

'Prayers of Sherkin': Old Vic, SE1 (0171 928 7616), tonight & Mon; then in rep to 15 Jun. 'Titus Andronicus': Nottingham Playhouse (0115 941 9419), Tues-Sat. 'Steaming': Piccadilly, W1 (0171 369 1734), to Oct.