If you think about it, castles took a lot of time (years), effort and money to build, so there would have to be a good reason to place them 'correctly'. (I'm assuming you're not referring to the quick, simple motte and bailey castles which were made of wood and built quickly (although often they were the where the later stone castle was built).
A castle existed for two main reasons.
1. At first, it needed to control the surrounding countryside. Therefore, it housed a small army (or was able to feed and water one). So it was often sited on a hill, by a river, or with easy access to a main highway.
2. It was for protection of the lord (and his family) in areas where other, powerful forces could attack. The peasantry had few weapons and were no real threat. But tribes living over the border (Scots!?) could be a threat, hence the need for protection or to act as a base for counter-raids.
A third reason developed out of the first two. As things became quieter, so the castle became an economic center. A town grew up around it and it grew and grew.
Of course, there is also the fact that a sufficiently rich lord could build a castle simply to show how powerful and wonderful he was, but that is really the same as reason 1: the need for control.
Castles built by King William where built to stop the amount of rebellions that they where having. The first version of castles that he built where motte and bailey castles (made out of wood). This worked. He built many of them around the country and forced people by fright to do what he told them to. Soon, he changed some of the castles to concentric castles (made out of stone). These didn't catch on fire easily, rott quickly and are very strong. These enforced Williams laws even more and also protected his country from invasions.
Because the kings at the time in history when castle were built, wanted to protect their lands from other kings. To do this, they had to build many castles.
Improvement:
There are many different types of castles in Ireland, of different periods, starting from fortified medieval castles that were built as defensive structures from around the 12th century to large pleasure type castles of the neogothic or Victorian period which were built by the very rich as a status symbol.
In medieval times, there were a lot of local Gaelic kings or chieftains that would have had conflict with each other and had their own fortified castles for this reason. There are also countless Norman Castles, which were the homes of landowning families, but were also fortified for fear of attacks.
Castles are important and a common feature around Ireland, with many fine castles still standing and open to the public. Ireland has many famous castles. Castles feature on various local emblems in Ireland, but not as any official emblem of Ireland.
defence settlement built by people like the conquering Normans
a castle
Power and protection.
very creepy
there are over 60 types of castle in ireland
england has the most castles or scotlend
Yes.
They are not specific castles. The emblem is meant to represent the strength and defiance of Dublin and its people.
WikiAnswers does not show pictures, sorry.
The harp is the official symbol of Ireland. The shamrock is a common symbol used to represent Ireland, though not the official one. Green can represent Ireland. The sports of Gaelic Football and Hurling, Ireland's two national sports, can represent Ireland. St. Patrick's Day events, like parades, can represent Ireland. These are some of the things, but there are others, like music.
12 MEPs represent the Republic of Ireland. 3 MEPs represent Northern Ireland. See the related question below.
Introduction of the English to Ireland and stone fortifications for e.g. castles etc
There are many castles, but none would be described as being palaces.