At common law, burglary had as its essential purpose the protection of the habitation of an individual. In a remarkable article, Professor Lauer has traced the history of the common law offense of burglary through the several legislative enactments in Wyoming. Theodore P. Lauer, Burglary in Wyoming, 32 Land & Water L. Rev. 721 (1997). In England, the essence of the offense was an invasion of the dwelling, both at common law and in subsequent legislative enactments. Id. at 723-30. This same concept was imported to America with later statutes expanding the protection from dwelling house to other kinds of structures, including business buildings. Id. at 730-32. In 1962, the Model Penal Code was promulgated by the American Law Institute as a summarization of prevailing notions regarding criminal offenses. Lauer, supra, 32 Land & Water L. Rev. at 732. Article 221 of the Model Penal Code addresses the crime of burglary, and it is defined in Section 221.1(1): "A person is guilty of burglary if he enters a building or occupied structure, or separately secured or occupied portion thereof, with purpose to commit a crime therein, unless the premises are at the time open to the public or the actor is licensed or privileged to enter. It is an affirmative defense to prosecution for burglary that the building or structure was abandoned." Lauer, supra, 32 Land & Water L. Rev. at 732. A parallel statement of the propositions is found in C.S. Parnell, Annotation, Burglary: Outbuildings or the Like as Part of "Dwelling House," 43 A.L.R.2d 831, 834-35 (1955): It is evident that the offense of burglary at common law was considered one aimed at the security of the habitation rather than against property. That is to say, it was the circumstance of midnight terror aimed toward a man or his family who were in rightful repose in the sanctuary of the home, that was punished, and not the fact that the intended felony was successful. Such attempted immunity extended to a man's dwelling or mansion house has been said to be attributable to the early common-law principle that a man's home is his castle. The jealousy with which the law guarded against any infringement of this ancient right of peaceful habitation is best illustrated by the severe penalties which at common law were assessed against a person convicted of burglary, even though the enterprise, except for the essential elements of breaking and entering a mansion house or dwelling house at night with intent to commit a felony therein, was unsuccessful. Rollin M. Perkins and Ronald N. Boyce, Criminal Law 255-56 (3d ed. 1982) states: That every man's house is "his castle" is a concept that has been echoed down through the ages and the social interest in the security of the "castle" has its origin in antiquity; for just as an animal or a bird resents any intrusion into its place of abode, so no doubt did primitive man. The terms commonly used to indicate the place are "dwelling" or "dwelling house," but the "word 'dwelling' imports a human habitation," and as a matter of common law, burglary is strictly an offense against the habitation. See Kanaras v. State, 54 Md. App. 568, 460 A.2d 61, 69 (1983), cert. granted, 350 Md. 280, 711 A.2d 871 (1998), reversed on other grounds, 357 Md. 170, 742 A.2d 508 (1999). Several states have recognized the increased seriousness of burglary when it is a dwelling of habitation versus a building or a business. This is based on the concept that the more serious burglary charge is intended to protect people while in places where they are likely to be living and sleeping overnight as opposed to protecting property in buildings such as stores, businesses offices or garages. See State v. Cox, 826 P.2d 656, 662 (Utah App. 1992); N.M. Stat. Ann. 30-16-3 (Michie 1994) (burglary in third degree involves dwelling house whereas burglary in fourth degree involves any other structure); N.Y. Penal Law 140.20 (McKinney 1999) (burglary in third degree involves building whereas burglary in second degree involves dwelling); Tex. Code Ann. 30.01 (West 1994) (habitation versus building); and Utah Code Ann. 76-6-202 (1998) (burglary in third degree unless involves dwelling, in which event the felony is second degree). Beginning in territorial days, Wyoming recognized not only the importance of protecting people in their homes, but in their businesses as well. The earliest reported Wyoming burglary case, Territory of Wyoming v. Conley, 2 Wyo. 331, 333 (1880), involved a railroad handcar house. The majority agreed a handcar house fell within the definition of "any other closed enclosure." 2 Wyo. at 334-335. Section 38 at 254 of the Criminal Laws of Wyoming (1876) defined burglary: Every person who shall willfully and maliciously and forcibly break and enter, or willfully and maliciously without force (the door or any window being open), enter into any dwelling house, kitchen, office, shop, storehouse, warehouse, malt house, stilling house, banking house, hotel, saloon, mill, pottery, factory, water craft, church or meeting house, railroad car, or any other close enclosure shall be deemed guilty of burglary. In Wyoming, as in many states, the development of case law addressed the meaning of the term "building." Seventy years later, this Court again considered the "building" portion of the burglary statute. In State v. Crouse, 69 Wyo. 85, 237 P.2d 481, 484-85 (1951), we held that a nearly collapsed powerhouse with no roof, one end and two sides absent, did not qualify as a building. Justice Blume concluded that although a functioning powerhouse may be a building, the destroyed powerhouse in this case was not a building. 237 P.2d at 485. This Court espoused the view that a house or building must have walls on all sides and a roof. 237 P.2d at 484. Thus, the common law concern with burglary as relating to human habitation continued. By 1957, the burglary statute, Wyo. Stat. Ann. 6-129 (1957), had been amended to read: (A) Whoever, intentionally enters, or attempts to enter, any of the following places without the consent of the person in lawful possession and with intent to steal or commit a felony therein may be imprisoned not more than fourteen (14) years: (1) Any building or dwelling; or (2) An enclosed railroad car; or (3) An enclosed portion of any automobile, vehicle, or aircraft; or (4) a locked enclosed cargo portion of a truck or trailer; or (5) a room within any of the above. (C) for the purpose of this section, entry into a place during the time when it is open to the general public is with consent. Under this version of the statute, this Court addressed the term "building" in Ash, 555 P.2d at 226-27. Ash involved entry of an enclosure attached to a liquor store, which consisted of a temporary wooden frame covered by plastic sheeting and a cement floor. 555 P.2d at 226. the enclosure had room for a person to move around. This satisfied the term "any building" because it served the basic purpose of an enclosure. 555 P.2d at 227. The distinction whether something qualifies as a building is not on the materials or methods of construction, but whether the building is "'protected from intrusion or trespass by some sort of material.'" Id. (quoting McCabe v. State, 1 Ga. App. 719, 58 S.E. 277, 278 (1907)). In 1973, the law was amended to include a locked or sealed building: Whoever, at any time, unlawfully breaks and enters, or attempts to unlawfully break and enter, into any locked or sealed dwelling house, office, storehouse, warehouse, church, meeting house, or building used for the purpose of religious worship, car factory, tool house, freight house, station house, depot, railroad car, cave or cavern, courthouse or other public building, or other building whatsoever, is guilty of a misdemeanor, and shall be imprisoned in the county jail not more than one year or [fined] a fine of not more than $ 500 or both. Wyo. Stat. Ann. 6-130 (Michie Cum. Supp. 1975). the following year, this Court struck as unconstitutional Wyo. Stat. Ann. 6-130 for vagueness because it failed to distinguish between essentially innocent conduct, breaking and entry for legal excuse, and criminally culpable conduct, criminal breaking and entry. State v. Stern, 526 P.2d 344, 348 (Wyo. 1974). In amending the burglary statute by the enactment of the Wyoming Criminal Code of 1982, the legislature enacted the "separately secured or occupied portion" language. Effective July 1, 1983, the statute provided: 6-3-301. Burglary. (a) a person is guilty of burglary if, without authority, he enters or surreptitiously remains in a building, occupied structure or motorized vehicle, or separately secured or occupied portion thereof, with intent to commit larceny or a felony therein. (c) a person may not be convicted both for burglary and for the offense which it was his purpose to commit after the entry or for an attempt to commit that offense, unless the additional offense is a violent felony. Wyo. Sess. Laws ch. 75, 3 (1982). Prior to its effective date, the legislature further amended Wyo. Stat. Ann. 6-3-301(a), so that it read: (a) a person is guilty of burglary if, without authority, he enters or remains in a building, occupied structure or vehicle, or separately secured or occupied portion thereof, with intent to commit larceny or felony therein. Wyo. Sess. Laws ch. 171, 3 (1983). the parallel nature of some phrases with the Model Penal Code is obvious. In 1985, Wyo. Stat. Ann. 6-3-301 was amended to read as it currently does. We decided Smith, 902 P.2d at 713 under this version of the statute. Smith involved a semitrailer, without wheels and without back doors, used for storage at a construction site. 902 P.2d at 712. Even though it was not completely enclosed by four walls and a roof, we held the semi-trailer was a building and therefore could be burglarized. 902 P.2d at 715. In Smith, we adopted the functional analysis from Ash that since the semi-trailer was planted firmly on the ground and was designed to shelter property, this Court held it qualified as a building under the statute. 902 P.2d at 715. The Wyoming legislature has not defined the term "separately secured or occupied portion thereof," and we look to other sources to consider what this phrase means. Our statute adopted this language from the Model Penal Code 221.1(1). the Model Penal Code defines "occupied structure" as "any structure, vehicle or place adapted for overnight accommodation of persons, or for carrying on business therein, whether or not a person is actually present." Model Penal Code 221.0 at 60. The comments to the Model Penal Code 221.1 explain that the premises protected by the burglary statute include "a building or occupied structure, or separately secured or occupied portion thereof." Model Penal Code 221.1 cmt. 3(b) at 71. the Model Penal Code comment explains that this language "takes care of the situation of apartment houses, office buildings, hotels, steamships with a series of private cabins, etc., where occupancy is by unit." Model Penal Code 221.1 cmt. 3(b) at 73. Implicit from this listing of examples is the proposition that a separately secured portion of a building be able to accommodate the presence of a human being. Although Wyo. Stat. Ann. 6-3-301 also does not define "occupied structure," it is defined elsewhere in the statutes to mean a structure or vehicle whether or not a person is actually present: (A) Where any person lives or carries on business or other calling; (B) Where people assemble for purposes of business, government, education, religion, entertainment or public transportation; (C) Which is used for overnight accommodation of persons; or (D) In which a person may reasonably be expected to be present. Wyo. Stat. Ann. 6-1-104(a)(v) (Michie 1997). In our view, there is very little reason to believe that the phrase "separately secured" would be intended to describe any different portion than the phrase "separately occupied."