Since times immemorial, most all types of swords were made by forging rather than casting.
Casting a sword is visually appealing, which is why you see that in the movies, but was not used in practice for multiple reasons, foremost of which were metallurgical concerns.
Casting steel requires significantly higher temperatures than forging (~1400°C vs. ~800°C) and unless you have a modern mould (along with a bunch of other modern metalurgical trappings), is likely to introduce impurities and faults into the material. This would be an expensive error, because getting an ingot of good steel would have been a non-trivial endeavour during most of history.
In contrast, forging is much gentler on the ingot, only takes two days or thereabouts (for the blade, that is) and hammering the blade can improve its properties with certain types of materials.
Also, the finished blade would usually quenched and tempered to keep it from bending.