Scattered along the coast at intervals of two or three miles, and generally at the summits of hills overlooking the sea, are "martello towers," fifty, sixty, and sometimes ninety feet high, and from forty to a hundred feet in diameter. They were erected early in the nineteenth century as defensive watch-towers, when the country was in dread of an invasion by Napoleon. The name was taken from similar towers in Corsica and Sardinia, where they were erected for protection against pirates in the time of Charles V. These towers are said to have originally had bells which were struck by hammers to alarm the people in case of danger; hence they were called "martello" towers, that being the Italian word for "hammer." It makes a Protestant ashamed when he reads the history of Drogheda and sees the ruins that Cromwell left there. Thousands of men and women and children were butchered in the name of the Lord by Cromwell's soldiers when he took that quaint old town by storm in September, 1649. It was a ferocious massacre, and Cromwell admitted the facts while proclaiming himself the agent of the Almighty to punish a rebellious people. This is what he wrote with his own hand: "The governor, Sir Arthur Aston, and divers considerable officers being there, our men, getting up to them, were ordered by me to put them all to the sword, and, indeed, being in the heat of action, I forbade them to spare any that were in arms in the town; and I think that night they put to death about two thousand persons. Divers officers and soldiers being fled over the bridge into the other part of the town, where about a hundred of them possessed St. Peter's Church steeple, some the West Gate, and others a strong round tower next to the gate called St. Sundays. These being summoned to yield for mercy refused. Whereupon I ordered the steeple of St. Peter's Church to be fired. The next day the other two towers were summoned. When they submitted their officers were knocked on the head and every tenth man of the soldiers was killed. The rest shipped for the Barbadoes. The soldiers in the other tower were all spared as to their lives only and shipped likewise for the Barbadoes. "I am persuaded that this is a righteous judgment of God upon these barbarous wretches who have imbued their hands in so much innocent blood; and that it will tend to prevent the effusion of blood for the future." Two of the towers have remained these two hundred and fifty years just as grim old Oliver left them, and there is much else of interest to the antiquarian in the town, although today it is given up to linen factories, flour mills, tanneries, and soap works, and has a large provision trade with England. It is the center of a prosperous agricultural community, and everybody seems to be doing well.