Spiked Barriers are good at stopping Cavalry and Siege weapons

Spiked Barriers are good at stopping Cavalry and Siege weapons.  They are the second easiest resource to build. buy kingdoms of camelot gems   I would recommend building 1,000 Spiked Barriers to start out with.

Once you have upgraded your Wall to a level 6, Blacksmith to a level 6 and your Fletching technology to a level 5 you will be ready to start building Crossbows. buy kingdoms of camelot gems  Crossbows will sit on your wall at the best vantage point to shoot at your enemies. These will really come in handy to take out any attacking forces that are able to get through your field defences. To start out with I would recommend that you build 5,000 Crossbows. Beware, Crossbows will require a large amount of wood to build, so ensure that your Sawmills are able to produce a large amount of wood.

You could also build Defensive Trebuchets, however, I would caution in doing this. The Trebuchet is excellent at destroying attacking Siege weapons, but it is only good for one shot. After the one shot you will need to rebuild and reload the Trebuchet.  cheap kingdoms of camelot gems It is an expensive wall defence to have. If you have resources to spare, then go for it, but I would invest in Crossbows instead. You could go ahead and build 200 Trebuchets.

However, be careful in how you build your wall and field defences. If you build them too fast and do not have an army to support your city, if defeated in an attack you will lose these defences and it will be extremely costly and timely to rebuild.