Magic in this world is not comon but not particularly rare either. Anyone can do it with the proper training and dedication but to be truly great at it can take several decades however it's fairly simple to take a two or three-year course ( if you can afford it) and come out with a handful of useful spells. Here are some spells commonly used by combat Wizards. I'm trying to figure out how a medieval Commander would deploy these spells and how that would change the medieval Battlefield.
Note: combat Wizards tend to be on the lower power side a usually only know a handful of common battle spells. Despite this they are still very expensive and most armies cannot afford to have a combat wizard Force larger than 20% of the overall Army.
Common combat wizard spells
Firebolt: fires a 2ft by 2ft ball of fire 120ft in normal weather conditions. 90ft in strong wind and 60 feet or less in very bad weather conditions. The temperature 800 to 3000 F depending on the experience and skill of the caster. ( approximate casting time 30-40 seconds) this spell very little energy can be used several dozen time befor the wizard s to stop and rest.
Ice : the wizard produces a focused beam of what appears to be light that lowers the temperature of everything the beam touches until the object or person has a temperature equal to that of the freezing temperature of water. How fast this happens depends on the temperature of the object. For people it can take up to a minute, however for things that are lower temperature then your average person it can go much faster. Effective range line of sight. Approximate cast time 40-50 seconds this spell is much more taxing and can usually only use less than 10 times before the wizard must stop and rest.
Firecone: produces a cone of fire from The Wizard hands approximately 6 ft wide at its widest point and 12 ft long. 800 to 3000 f depending on the skill of the caster. Approximate casting time 10- 20 seconds. This spell can be used usually around 10 time for the user must stop and rest.
Tornado: a spell that produces a small tornado 10 feet across approximately 150-200 miles per hour that last between 5-15 minutes depending on the strength of the caster. The spell is very tiring and most Combate Wizards cant use it more the five times before stoping to rest.
How would the addition of these spells Change medieval military strategy and would they be worth the price of hiring combat Wizards?