For some reaons higher level, initiated masons don't want their lower level brothers to know the origins of freemsonry.
Freemasonry was founded in the 17th century, when Amsterdam was the opium and money centre of the "civilised" world.

In the 9th century, King Pepin of Italy, son of Charlemagne King of the Franks, tried unsuccessfully to conquer Charlemagne's enemy Venice.
This of course doesn't mean that Venice was still the enemy of the Carolingians in the 13th and following centuries, but that is apparently the conclusion of the Larouchians.

In the 13th century, the Venetians were at their top of military power and aimed to create a new Roman Empire with Venice at its centre . They expanded into the Italian mainland, Greek islands, and the Black Sea. They helped to defeat the Hohenstaufen rulers of Germany and Italy.
Venetian intelligence assisted Genghis Khan in his brutal campaign against powers that resisted Venice.
Later, after a series of wars Venice and Genoa joined forces.

The Venetian bankers (a.k.a. Lombards) looted Europe through usurious loans. In the years after 1255, Henry III of England became insolvent after getting Lombard loans at 120-180% interest to fight foreign wars . These loans started the Venetian Party in England.
When the Lombard bankers went bankrupt because the English didn't pay, a collapse of the European economy followed and the Black Plague that depopulated the continent. In the midst of the chaos, the Venetians encouraged their ally Edward III of England, to wage war against France (the Hundred Years War 1339-1453), and found the Most Noble Order of the Garter (around 1348).

While Venice had always been the enemies of science, Paolo Sarpi realised that the Venetians must now present themselves as the great champions of science, to seize control, corrupt and ultimately destroy the scientific community from the inside, through Aristotelian formalism and sense certainty.

Sarpi sponsored and directed the career of Galileo Galilei, who was used for a counterattack against the Platonic method of Johannes Kepler.
The supposed founder of Physics, Isaac Newton’s main interest was alchemy. His sources were kooks like Elias Ashmole, the Rosicrucian leader of British speculative Freemasonry:

The following has more information on how the Venetians created Freemasonry in England.
In 1616, the Protestant-Anglican royal marriage of James I's daughter to the Elector of Palatine was the talk of England. For Venice, a significant counterweight to the Habsburgs.

Also in 1616, the first Rosicrucian tract - the "Fama'' - is written, calling for the formation of a Brotherhood of the Rosy Cross. It is not too distant from what Sarpi's friend, Francis Bacon, is calling for. Shortly thereafter, another Rosicrucian document - the "Confession'' - is published.
Both written in German and circulated in the territory of the Elector of Palatine.

This is followed by several other Rosicrucian documents, all claiming to have solved the riddle of the relationship between the microcosm and the macrocosm.
One of these books was written by Robert Fludd, who is attacked by Kepler as a mystic who uses numbers as a form of kabalistic symbolism.

The beginning of the Long Parliament and a series of meetings in England, in 1640, led to the creation of the British Royal Society. Robert Moray in Edinburgh in 1641 is the first recorded induction into the Freemasons, quickly followed by Elias Ashmole. Both Ashmole and Moray were founding members of the British Royal Society.
The other major explicitly Rosicrucian figure was Isaac Newton, who had copies of both the Fama and the Confessio in his library.

Historian Frances Yates quotes one De Quincey:
Freemasonry is neither more nor less than Rosicrucianism as modified by those who transplanted it in England, whence it was re-exported to the other countries of Europe.
An announcement for one of the Freemason meetings in 1676 reads:
To give notice that the Modern Green-ribboned Cabal, together with the ancient brotherhood of the Rosy Cross: the Hermetic Adepti and the company of Accepted Masons...

The last is a much longer article, whose main value for me is that it doesn't come from LaRouche, and independently confirms the LaRouche information...

According to John Robinson, all of the original members of the Royal Society were Freemasons, with Rosicrucian elements.

Metaphorically Rosicrucians were Rose Cross men - men who used Bacon's discovery device (which has a compass design in the plays) to make the metaphoric voyage beyond the pillars of Hercules in search of the New World of the sciences.
Freemasonry society. In Bacon's time it was a true secret society.

The Temple of Solomon of Freemasonry is a model of the universe. The compass with the Rosicrucian rose is a metaphoric model of the world. Both are built into the First Folio, with its design of the 32 directions of the compass, and the 36 decans of the zodiac.

The Rosicrucian Fraternity was designed as a metaphoric complement to the Freemason Society (or vice versa).
There is a close affinity with the New Atlantis - the land of the Rosicrucians: