|When in the winter of 1704-5 Marlborough and his architect, John Vanbrugh, surveyed Queen Anne's gift of Woodstock Park and chose the site for the palace, they realised that in direct line with its main (north western) approach lay an awkward valley, wide, deep and precipitous, through which trickled the Glyme stream and its tributaries, forming a marsh. To cross this marsh there were two raised causeways with s mall bridges, used as shortcuts to Woodstock and Oxford; and, formerly, as two ways for pedestrians to approach Woodstock Manor.
Vanbrugh saw this marsh as ornamental water crossed by the finest bridge in Europe. Marlborough, more cautious, consulted Wren, who prescribed a far less pretentious and less costly bridge and, for the steep palace approach, a sweeping circular drive. His plan, Òstuck full of pins' as Vanbrugh described it, was not adopted. Vanbrugh's persuasiveness, which was considerable, won the day.
If Wren had had his way, a bridge only 15 feet (4.6 metres) high would have carried the grand approach over the Glyme; whereas the arcade on the top of Vanbrugh's, though never completed, was planned to have soared to 80 feet (24 metres ).
When in 1708 the bridge was founded, there were still gargantuan problems, not the least of them how to link it with the sides of the valley. Marlborough had more than once to be reassured by Queen Anne's gardener, Henry Wise, and by Vanbrugh that they would find enough earth to fill the chasm, even though it meant levelling the hill on which the ruins of Woodstock Manor stood and using some of that masonry as rubble filling for the bridge.
Bartholomew Peisley, the mason who built the bridge, under Vanbrugh's direction, was Òvery proud and overjoyed' when in 1710 the main arch, 101 feet (almost 31 metres) wide, was keyed, Òit being a great and nice piece of work'.
Everything about the bridge is extraordinary and much of it is puzzling. No ground plan has survived. All we have is an elevation showing the proposed superstructure in the manner of a viaduct or of the Pont du Garde. Sarah 1st Duchess of M arlborough vetoed the arcade. ÒI made Mr. Vanbrugh my enemy', she wrote, Òby the constant disputes I had with him to prevent his extravagance.' The immensity of the Grand Bridge and its cost was one of the main subjects of their dispute. The Duchess scath ingly told a friend that she had counted thirty-three rooms in it, that there was a house at each corner and that what made it so much prettier than London Bridge was that you might Òset in six rooms and look out at window' while the coaches rumbled over your head. Vanbrugh in its defence went so far as to assure her that if, when it was finished, she found a house inside it she would go and live in it. Nothing was more unlikely; and indeed there is no evidence that it was ever lived in, though some rooms have fireplaces and chimneys, and one large windowless chamber has been plastered and fitted with an elliptical arch as though for a theatre. Old guidebooks describe the bridge as a cool retreat in summer, and no doubt many a picnic was enjoyed in the su nnier rooms. Unfortunately it is no longer safe to enter now.
Soon after Marlborough's death, in 1722, his widow called in Colonel John Armstrong, who had been his chief engineer, to re-plan the water-works in the park. The River Glyme, flowing under the Grand Bridge, was channelled into canals that beneath the middle arch leapt a cascade before broadening into a formal pool on the western side.
The northernmost arch of the bridge was used to house Aldersea's engine, a huge paddle-wheel affair, which pumped spring water from Rosamond's Well to the East Gate cistern. This stood on the leads, where the flag now flies, and provided the eastern half of the palace with water. As a water-supply it worked well but, as scenery, the canals looked inadequ ate and called forth such quips as Pope's:
ÒThe minnows, as under this vast arch they pass, murmur, 'How like whales we look, thanks to your Grace!''
To judge from old engravings, the canal and pool Sarah favoured looked very bleak - the pool it self was designed with a compass and was like a huge version of the Versailles fountain-basins. But formality was the fashion, and for those who admired it the results at Blenheim brought praise. Sarah herself was delighted. ÒThe canal and basin', she tol d her suitor, the Duke of Somerset, in 1723, Òlook very fine. There is to be a lake and a cascade on the side of the Bridge next Woodstock . . . Sir John [Vanbrugh] never thought of this cascade,' she complacently adds, Òwhich will be the finest and large st that ever was made . . . The fine green meadow between the house and the woods is to remain as it is, and I believe your Grace will think in that, Nature cannot be mended, tho Sir John formerly set his heart upon turning that into a lake, as I will do it on the other side, and I will have swans and all such sort of things . . .'
When Sarah died in 1744, Blenheim waited twenty years before reflecting the change of fashion from formality to naturalism in its own magnificent lake. Then, with one mast er-stroke, 'Capability' Brown was able to change the landscape. After building a dam and cascade near Bladon, he sliced through the causeways once leading from Woodstock Manor across the marsh towards Woodstock and Oxford, leaving a small strip now known as Queen Elizabeth's Island. Thus he let the Glyme run through the bridge, engulfing the ground floor, and spread out into lakes on either side of it. Another mile downstream Brown made minor cascades of great beauty at the point where the Glyme falls int o the Evenlode. This then joins the Thames, which he boasted would never forgive him.
ÒIf these two lakes had been designed as one vast expanse of water,' comments Brown's biographer, Dorothy Stroud, Òthe effect would have been tedious. As it is they are both united yet divided by Vanbrugh's bridge, from which the two parts spread out like the loops of a nicely tied bow.' True, the cascade Sarah had been so proud of is now under water; but Brown's Grand Cascade still tumbles into the lake at its western end.
At the Grand Bridge the northern arch had been cleared of its engine before the ground-floor rooms were flooded. This last event caused much anxiety. Could the bridge withstand it? It could and did. But the visible height of the bridge is now a great deal less than Vanbrugh intended. Its base is submerged, and the arcaded superstructure with which Vanbrugh planned to crown i t has never been built.
ÒThe lake at Blenheim', wrote Sir Sacheverell Sitwell, Òis the one great argument of the landscape gardener. There is nothing finer in Europe.'