Al Hazm Castle – according to the Ministry guide-book.
Located in Al Hazm town in the District of Rustaq. It was built by Imam Sultan bin Seif the 2nd in ( 1123 A.H.–1711 A.D.) when he established Al Hazm town as a capital of Oman instead of Rustaq. The Castle is distinctive from other Omani Castle and forts by its magnificent shape and massive building. It contains the tomb of its builder – Imam Sultan bin Seif the 2nd.
The builder Imam Sultan bin Seif was the 5th ruler of the Ya’rruba dynasty of Imams; he was the grandson of the Imam (of the same name) who made the Portuguese an offer they could not refuse! they all left, after many years of attempting to subjugate the people.
This Fort is an outstanding example of Omani Islamic architecture and was built for defence against cannon. The roof is built on columns, and contains no wooden supports. Its walls can withstand the impact of cannon balls due to it being at least 3m thick at any point.
It has the outside appearance of being far larger than it really is, helped by tall walls and two towers, one on the Northwest corner & the other on the Southeast – giving almost 360 degrees of cover.
Another interesting fact; it used an advanced form of vaulted arch which was a major departure from the use of straight lines, along with post & lintel construction as had been seen in most of Oman’s earlier defensive constructions.
There are the usual defensive details such as multiple offset doors, pits just after a door (covered with planks of wood, removed when under attack) murder-holes above doors (think boiling oil or fire) along with hidden escape passages.
I have visited this fort on & off, many times as it not only has some of the most friendly and helpful custodians, but its main feature is the impressive collection of cannon.