I would go even further by trying to let the battery charge all day, but I suspect the battery is permanently damaged. Unfortunately a completely discharged battery will many times prevent an Apple laptop from even powering on since all the power is being directed to battery instead of to the main system.
Even if @John Galt's suggestion works, the battery has most likely been damaged from being stored too long without any charge on it. Lithium batteries need to be stored with a charge between 20% to 60% at all times, so every so often you will need to connect the power to recharge the battery to keep the charge level between these levels to keep the battery healthy.
Here is an Apple article with details to maximum battery life including how to store a device with a Lithium battery (pretty much all devices with batteries these days). See the very bottom of the article for storing devices with Lithium batteries:
Batteries - Maximizing Performance - Apple