We can use the half-life formula to find the amount of Radium-226 that will remain after 2000 years:
A = A₀ (1/2)^(t/T)
where A₀ is the initial amount, A is the final amount, t is the time elapsed, and T is the half-life. Substituting the given values, we get:
A = 300 (1/2)^(2000/1590) = 117.2 mg (rounded to one decimal place)
Therefore, approximately 117.2 mg of Radium-226 will remain after 2000 years.