Europeans were originally motivated to explore the seas to discover previously unknown lands, especially after the contact with America, where europeans found all kind of valuable goods. The portuguese were the first to pursue maritime exploration, soon to be followed by the spaniards.
The gradual muslim conquest by the mughal empire.
Probably very stressful and very difficult
It's approximately 450-1450 AD
The answer is siege.
Siege, also known as blockade or encirclement, is an attack where a military force surround a city or fort in order to make them surrender. This would trap the enemies with the force encircling them. The force basically encircles them then cuts off their resources and supplies and compels or persuade them to surrender.