Full Moon over Leiden

Today Leiden eats hutspot, herring and white bread for 3 October 1574, when the Sea Beggars' boats sailed over flooded fields and broke the Spanish siege. John Lothrop Motley told the story in 1855. I checked his weather against the Moon.

September and October 1574

Moon phases from NASA's table for 1501–1600 (Fred Espenak), which gives pre-1582 dates in the Julian calendar. The drawing for each day is interpolated between those four phase times, at noon. Events are Motley's, in his dates.

The spring tide he was waiting for

On 28 September a dove brought the city a letter from Admiral Boisot: relief within a few days. The next morning the vanes pointed east and the water fell. Motley says Boisot then wrote to the Prince

that if the spring-tide, now to be expected, should not, together with a strong and favorable wind, come immediately to their relief, it would be in pain to attempt anything further

Spring tides come with the new and the full moon. NASA's table puts a full moon on 30 September 1574, at 13:14 Universal Time. So Boisot was right to expect it that week. The gale came the next night, "from the north-west, shifting after a few hours full eight points", and stacked a storm on top of the biggest tides of the month. In 24 hours the water under the fleet at North Aa went from nine inches to more than two feet.

The Moon only adds the timing; it does not show how much of the rise came from the tide and how much from the wind. Nobody measured that in 1574.

The anniversary is ten days early

Holland kept the Julian calendar until 12 January 1583 (Wikipedia, Adoption of the Gregorian calendar, citing Fruin). So Motley's 3 October is a Julian date. On today's calendar the boats came in on 13 October 1574. Leiden celebrates on the right number and the wrong day, ten days before the sun is back where it was. The calendar above switches between the two.

The boy on the fort

Motley has a boy in the story. At dawn on the 3rd the fort at Lammen was silent; then "one solitary boy was seen to wave his cap from the summit of the fort". He had watched the Spaniards' lanterns leave in the night and walked out alone at daybreak. In Motley's version, written in 1855, the boy has no name and no pot.

The Leiden legend that every child learns gives him both. The Dutch Wikipedia article on Cornelis Joppenszoon (1561–1591) calls him an orphan who found a pot of hutspot the Spaniards had left at Lammen. It adds that the orphan part was probably invented for the 1774 centenary, that another version names a Ghijsbrecht Corneliszoon Schaeck, and that the Leiden historian Johannes le Francq van Berkhey said the boy was his own ancestor. That article dates Berkhey "1769–1811". His own article and Wikidata give 1729–1812. The wrong span matches his publishing years: the first volume of his Natuurlyke Historie van Holland in 1769, and his cattle history of 1805–1811.

What stands on what