Original: Of the six Overtures Francesco Maria Veracini wrote for Prince Friedrich Augustus in Dresden, most are in either F major or B-flat major because of the limitations of the winds in the Prince's orchestra.
Simplified: Of the six Overtures Francesco Maria Veracini wrote for Prince Friedrich Augustus in Dresden, most are in either F major or B-flat major because the prince's orchestra had a lot of wind instruments that played best in these keys.