On a perfect weekend for parties in the garden, I was lucky enough to be invited to two such events. The first, on Saturday, was a well-managed celebration in the beautiful grounds of Magdalen College, marking the 550th anniversary of William of Waynflete's signing of the institution's foundation charter on June 12, 1485. (Chris Koenig writes about this today on Page 21). More than 2,000 guests enjoyed a delicious tea and a programme of events that included chauffeured punt rides, guided climbs up the 167 uneven steps of the tower, two organ recitals and an affecting performance in the cloisters (Thomas Tallis, Thomas Weelkes, Thomas Morley and others) by the college choir under its director, Bill Ives.

I was pleased to find a number of old friends among the crowds strolling and seated on the sun-dappled lawns. None was of such venerable age, however, as the oldest member present, Arthur James, who came up in 1935. It was delightful, too, to see so many children there, enjoying the Mad Hatter's tea party and face-painting beneath Magdalen's celebrated plane tree. I felt privileged to have been at this very special event, and was most grateful for the courteous invitation from the President, David Clary.

On Sunday, the Gray panama was out once more for a lunch party in the garden of Felicity Bryan's home in Kidlington. This was another large affair, with 140 guests gathered to congratulate our hostess on 20 successful years in charge of the literary agency that bears her name - one of the best-known in the business. A former journalist on the Financial Times and the Economist, Felicity later worked with Curtis Brown before setting up on her own, challenging the metrocentric attitudes of the literary scene with a base in Oxford.

In the course of a witty speech at the party Catherine Clarke, who joined her as an agent from the OUP in 2001, noted: "Felicity . . . proved that London is not in fact the centre of the universe . . . but that in fact it had moved to Oxford." My first ellipsis hides the identity of her earliest co-workers Margaret Nairne, Michele Topham and Carole Robinson.

The quartet of agents, each of whom has her own list of celebrated clients to handle, is completed by Sally Holloway (joined 2002) and Caroline Wood (2006). Jo Frank spots new talent; Julie Wixey handles the hundreds of author's royalty statements.

"It probably hasn't escaped your notice that we are all women," Catherine told lunch guests - prompting me to wonder why the outfit isn't styled, with apologies to Alexander McCall Smith, 'The No. 1 Ladies' Literary Agency'. But that would be to forget Felicity's husband Alex, a director of the firm.

Though McCall Smith is not a client of the agency, a no less celebrated Scottish author is (I am assuming that Rosamunde Pilcher now qualifies as a Scot, having lived in Dundee since 1946, though she was born in Cornwall). The 83-year-old novelist, whose many books have been international best-sellers, was on sprightly form at the party, and a delight to talk to. It was a pleasure, too, to meet her eldest son Robin Pilcher who has now achieved literary fame of his own.

Literary lions and lionesses were naturally present in large numbers. I was pleased to find I was at the same table as the historian and broadcaster John Julius Norwich, the son of the celebrated society beauty Lady Diana Cooper and father of the biographer Artemis Cooper. Artemis, with whom I am pictured above, is following up her highly acclaimed life of Elizabeth David with that of the scholar and war hero Patrick Leigh Fermor.

Among others whom I saw or met - how easy it is to slip into the style of the late Betty Kenward, 'Jennifer' of Harper's & Queen - were Sir Roy Strong and James Naughtie. Actually, I met them both, Naughtie as he headed home to an early night in bed as a prelude to a 3am reveille for the start of a week of work on Radio 4's Today programme.