Maryland Constitution of 1867 Art. 11, § 4

The regular session of the City Council of Baltimore, (which shall be annual,) shall commence on the third Monday of January of each year, and shall not continue more than ninety days, exclusive of Sundays; but the Mayor may convene the City Council in extra session whenever, and as often as it may appear to him that the public good may require; but no called, or extra session shall last longer than twenty days, exclusive of Sundays.