While First Ladies have continually captured the interest of the nation's citizens, the role of the chief executive's wife has not remained static throughout history. In fact, she has not always been called the First Lady. In the earliest days of the struggle to define the role, one of the most heated areas of contension was the debate over an appropriate title for the chief executive's wife. On the national level, there was little consensus on how to address Martha Washington, the wife of the the first American president. The media, as well as the public at large, suggested several epithets, such as Lady Washington, Mrs. President, and presidentress. Perhaps as a reflection of America's English heritage, the title of Republican Queen was even considered. However, none of these designations gained popular acclaim. 
The title "First Lady" did not come into national prominence until the era of the Civil War. William Howard Russell, a British journalist, is attributed with the first usage of the term in 1863. While writing about his experiences during a trip through the war-torn South, Russell proportedly called Jefferson Davis' wife , Varina, the "first lady of the Confederacy." A few years later the term was first used in America by journalist Emily Briggs (whose pen name was "Olivia"). In an 1870 newspaper column "Olivia" wrote, "at Mrs. Washington's receptions in both New York and Philadelphia, the first lady in the land received precisely after the manner of Queen Charlotte." "Olivia" also referred to the contemporary chief executive's wife, Julia Dent Grant, as the "first lady" regularly in her columns. In 1877, journalist Mary Clemmer Ames appropriated the title when she reported on the inauguration of Rutherford B. Hayes and "first lady" Mrs. Lucy Hayes. Finally, as if to signal the popular acceptance of the honorific title, in 1911 playwright Charles Nirdlinger composed a work about Dolley Madison and entitled it First Lady of the Land. 
Consistent with the national trend, at this time the local press began to use the title regularly to describe the wives of Maryland's governors. For example, both The Evening Capital and The Advertiser-Republican newspapers referred to Ellen Showell Goldsborough, wife of Governor Phillips Lee Goldsborough, as the "First Lady of Maryland" when she first came to Annapolis in 1912. 
However, in Maryland, there is also evidence that the press referred to the governor's wives as Official Hostesses earlier than they called the women First Ladies. In 1902, The Evening Capital called Mary Smith, wife of Governor John Walter Smith, "Maryland's Official Hostess."  Unlike the term First Lady, this title specifically highlights one of the most important responsibilities of the woman presiding in the state capital---her role as a hostess. Also, it is significant that the title Official Hostess can apply to a woman who presides over the social happenings at the capital without being married to the governor. For example, in 1911, The Evening Capital referred to Miss Lynn Shaffer, niece of Governor Austin L. Crothers, as "the state's Official Hostess."  While the period newspapers often use the term interchangeably with First Lady, whether or not the hostess is married to the governor, in the context of these biographical profiles, the title Official Hostess will be reserved for the women who were not married to the governors, but acted as the designated hostess in the state capital.
Undoubtedly, the process of defining and refining the role of the chief executive's partner will continue. When the first woman takes the oath of office as Maryland's Governor, perhaps the state will have its first "First Gentleman and Official Host" presiding in the capital. However, whether the chief executive's spouse is man or a woman, it is certain that the role ascribed to him/her will continue to evolve according to the customs of the day and the personalities of the individuals who fill it.
Note on Sources
First Ladies and Official Hostesses Project Page