So long as William the Silent lived, that great prince was all in all to his country, and Barneveld was proud and happy to be among the most trusted and assiduous of his counsellors.
When the assassination of William seemed for an instant to strike the Republic with paralysis, Barneveld was foremost among the statesmen of Holland to spring forward and help to inspire it with renewed energy.
The almost completed negotiations for conferring the sovereignty, not of the Confederacy, but of the Province of Holland, upon the Prince had been abruptly brought to an end by his death.

To confer that sovereign countship on his son Maurice, then a lad of eighteen and a student at Leyden, would have seemed to many at so terrible a crisis an act of madness, although Barneveld had been willing to suggest and promote the scheme.

The confederates under his guidance soon hastened however to lay the sovereignty, and if not the sovereignty, the protectorship, of all the provinces at the feet first of England and then of France.
Barneveld was at the head of the embassy, and indeed was the indispensable head of all important, embassies to each of those two countries throughout all this portion of his career.

Both monarchs refused, almost spurned, the offered crown in which was involved a war with the greatest power in the world, with no compensating dignity or benefit, as it was thought, beside.
Then Elizabeth, although declining the sovereignty, promised assistance and sent the Earl of Leicester as governor-general at the head of a contingent of English troops.

Precisely to prevent the consolidation thus threatened of the Provinces into one union, a measure which had been attempted more than once in the Burgundian epoch, and always successfully resisted by the spirit of provincial separatism, Barneveld now proposed and carried the appointment of Maurice of Nassau to the stadholdership of Holland.