Rebound
"a poem, upon the late victory obtained by the Prince and Duke of Marlborough, and Union of the two kingdoms"
references to J Gaynam are few. There are some to a "reverend" of the fleet.

John Churchill, 1st Duke of Marlborough, Prince of Mindelheim, 26 May 1650 – 16 June 1722 O.S),[1] was an English soldier and statesman whose career spanned the reigns of five monarchs through the late 17th and early 18th centuries.

Becoming de facto leader of Allied forces during the War of the Spanish Succession, his victories on the fields of Blenheim (1704), Ramillies (1706), Oudenarde (1708), and Malplaquet (1709), ensured his place in history as one of Europe's great generals.
The military setbacks of 1707 continued through the opening months of 1708 with the defection of Brugge and Gent to the French. Marlborough remained despondent about the general situation, but his optimism received a major boost with the arrival in theatre of Prince Eugene, his co-commander at Blenheim. Heartened by the Prince's robust confidence, Marlborough set about to regain the strategic initiative. The plan was in principle a repeat of the double invasion of the previous year, this time with the main blow to fall in the Low Countries. After a forced march, the Allies crossed the river Schelde at Oudenaarde just as the French army, under Marshal Vendôme and the duc de Burgundy, was crossing farther north with the intent of besieging the place. Marlborough – with renewed self-assurance – moved decisively to engage them.[98] His subsequent victory at the Battle of Oudenaarde on 11 July 1708 demoralised the French army in Flanders; his eye for ground, his sense of timing and his keen knowledge of the enemy were again amply demonstrated.