Below found the Marshal's detailed strategies in Stronghold Crusader.
Longarm runs a small and somewhat simple economy. He emphasizes on iron production and less to stone and wood. He has numerous dairy farms backed up with some hop farms for Ale production. He sometimes buys in apples for food variety. He also makes use of positive Fear Factor to gain money and boost unit morale.
Because the Marshal does not buy in weapons, he tends to build up a lot of gold in the game, which is rather pointless, as he doesn't have a large castle to maintain and repair during a siege (unlike Emperor Frederick, who also doesn't buy in weapons).
Longarm is slow in building up his attack forces as he does not buy in weapons. When he does besiege a castle, his attacks are like a Crusader version of those of Sultan Abdul with a usually modest number of European archers and European swordsmen, and like him, the archers attack well before the swordsmen arrive. However, the Marshal will also throw in a trebuchet or two as well. More archers are brought if a moat is present, and his swordsmen often turn to destroying farms and other structures.
The main strength of the Marshal however, lies in harassment. Numerous stables provide a steady stream of knights to frequently raid and destroy hostile buildings, preferably farms, quarries and mines. Sometimes one catapult or two will pound stones on these buildings, but knights perform much faster, so they are rarely seen causing heavy damage.
Longarm builds smaller castles with weak defense. For all of his castles, he encloses his granary, armoury and market, while for at least some of his castles, he leaves his courtyard undefended. His walls are thin with crenulation and consist of perimeter turrets and small gatehouses. He stations archers on strategic locations and knights will guard his campfire. Occasionally if his campfire is too crowded with knights, something very unusual may happen in that some of the knights, on horseback, end up on top of the keep or walls.
Sometimes the Marshal digs a moat near walls and sometimes encloses his good things with it. The Marshal sends a small force of archers and knights when provocated by enemy troops.