It is not known why Guarnerio's family left Lombardy, but it may have had something to do with the Napoleonic Wars. The French conquered Lombardy in 1797, the year before Petro was born, and integrated it into their new "Italian Republic," the president of which was Bonaparte himself. The fact that the Guarnerios left Lombardy and travelled to England, rather than elsewhere, suggests they were strongly opposed to Napoleon's rule.

From 1844 foreign nationals could apply to become a British subject. Peter Guarnerio's naturalisation certificate was issued by the British Government on 3 June 1847 - a copy of it still survives at the National Archives in London (TNA reference HO 1/25/610). By 1851 Peter was living in Huntingdon High Street with his wife Mary (born in Northamptonshire) and their children Druscilla, Sarah, Augusta, Peter junior, Angelina, and Margaret; his other children Gaspere, Carolina and Louisa had already moved out by this time.

On 4th April 1848 Gaspere Guarnerio reported to the magistrates that a watch had been stolen from his father's shop:

The silver watch now produced is the property of my Father - I saw it in a tray in the shop window between 9 and 10 o'clock this morning - the value of the said watch is twelve shillings.

Employee John Pratt was working in the shop when he heard the window being smashed, and saw a man take the watch. Pratt gave chase down the High Street and caught the thief, who was James Jones, and who later admitted to the crime in front of the magistrates.

The St Ives connection

This was not the only branch of the Guarnerio family in Huntingdonshire. Peter's brother Angelo Guarnerio was a silversmith living in St Ives during the 1840s, and sold clocks and watches from a stall in St Ives market. In November 1843 Burton Smith of Alconbury attempted to rob his stall during a gusty day. Angelo told the magistrates later that he had briefly turned his back to Smith "while I was holding my stall down to prevent it being overturned by the wind," and Smith took this opportunity to steal a silver gilt watch worth about five pounds.
 

Smith then made the elementary mistake of going to another local watchmaker's, Charles Wratten, on that very same afternoon to try to sell the watch. Angelo spotted Smith there, but Smith denied ever being at Angelo's stall. After Angelo had left to find a witness Smith ran out of the shop, and Wratten gave chase (after stopping to put his hat on), accompanied by a constable. Smith was apprehended on the drove between Hartford and Wyton, and the watch was recovered.