In a setting with limited magical fire-power, most monsters and creatures get ramped up significantly in terms of fear and power. A mixed blessing is the nature of many of these things - by definition, many of them are uncontrollable and therefore make for poor tools. This does not apply to a golem. Being made of construction materials, your standard weapons won't do much. Combine this with the fact they're mobile meaning scoring a hit with some form of siege weapon is pretty unlikely. As we specified at the beginning, your traditional magical artillery battery is out too. So how do you deal with such a thing?
Obviously, this depends massively on the construction materials and creation methodology, but the most common types would likely be stone and clay, with the rare iron golem appearing. Of course, there will always be more exotic and outlandish materials used for specialist application. Methods of creating golems include
- Creation via rituals, either divine or arcane
- A scroll with the name of (a) God written upon it inserted into the inert form
- Use of limited quantities of incredibly rare minerals
- Imbuing the form with a 'spark of the divine' or similar phenomena
Assuming the use of a common, workable material for the majority of the body, individuals without magical support would be forced to fight a golem using unconventional tactics. A possible strategy which could be used would revolve around three main elements - bait, trippers and sappers. A pair of horsemen would hide, a rope or chain strung between them. The bait would attract the attention of the golem, who would then approach. At this point, the riders would attempt to bind the legs of the golem using the chain/rope, causing it to trip. Thus disabled, the sapper team would then move quickly, damaging the material of the golem with appropriate tools - mining picks for stone for example. Ideally, the golem would be disabled sufficiently in a single operation, but it is not impossible that multiple trips would have to be made before the golem was rendered ineffective. Aiming for a 'mobility kill' via the legs would increase the likelihood of a single strike being effective, although a golem would have the ability to drag itself around unlike modern military vehicles which are targeted for mobility kills.
Golems created with the name of a God or with a 'brain' of rare materials could be dealt with by targeting this control element - though practically this would require an incredibly brave individual to mount to golem, survive the attempts to dislodge them whilst also removing, damaging or otherwise disabling this control element which is most likely armoured, hidden or otherwise protected. This work is far better suited to adventurers rather than the common soldier.
Given enough time, golem-traps could be constructed utilizing either deep pits or soft sand areas, in which the naturally heavy golems would become trapped and therefore unable to continue the assault.
Of course, none of this is needed with the application of either magical firepower/items or more accurate siege weapons. Fighting a golem without these things toe-to-toe is suicide, which is why the secrets of golem-crafting are not common knowledge.