The assignments of error complain, first, that the court erred in overruling the demurrer to the petition; second, that the court erred in declaring the assessment of petitioner’s property unlawfully made.

I. We think a proper consideration of all substantial questions suggested by the demurrer to the petition can be had by ascertaining (A) whether the assessment for taxes of 1896 was void because made by Biglow, instead of the auditor of the city of Tampa; (B) whether the city of Tampa had power, by contract or otherwise, to exempt from taxation the various properties alleged in the petition; (C) whether the *694exemptions of taxable property by the city, the omissions of taxable property from its tax rolls, and the placing thereon of property legally taxable, in order to make the rolls apparently valid, bat with no intention on the part of the city of collecting the taxes due thereon, will justify a court in setting aside the whole assessment in a proceeding by petition under our statute, section 1542, Revised Statutes.

A. We think the first question must be answered affirmatively. Section 4 Chapter 4496, approved May 29, 1895, being the present charter of the city of Tampa, provides that “the government of said city shall be carried on by the following officers: A mayor, eleven councilmen, a marshal, a clerk, a treasurer, a municipal judge, a tax collector, and auditor who shall also be assessor of taxes, a chief of the fire department, and such other officers as may be created by ordinance of the city not inconsistent herewith, and all of said officers shall be qualified electors of said city of Tampa, and shall perform such duties and receive such compensation as may be prescribed by ordinances of the city of Tampa, not inconsistent with the provisions of this charter.” By 'section 10 it is provided that the mayor shall, by and with the consent of the city council, appoint some suitable person to be called the auditor of said city, who shall also act as assessor of said city, who shall give such bond as the council may direct and whose duty and compensation shall be fixed by ordinances, except as herein provided. Section 31 makes it the duty of the tax assessor of the city, between April 1st and July 1st of each year, to ascertain by diligent inquiry all taxable personal property and all taxable real estate in the city and the names of the persons owning same on April 1st in each year, and to *695make an assessment of all taxable property. It requires him to visit and inspect all real estate and affix a valuation thereon, and he is to require the owners of personal property to return and value same under oath, which he is authorized to administer, and any person refusing to ¡make such oath is not permitted afterward to reduce the valuation of such personal property for that year. By section 34 the assessor is required to value all personal property not returned under oath according to his best judgment and information. Other provisions of the charter require the assessor to make out assessment rolls in the manner specified therein, to meet with the city board of equalization on the first Monday in July of each year, for the purpose of reviewing the assessment rolls, to calculate and carry out the several amounts of taxes, after the amount to be raised has been determined, and after ■completing the rolls to append to them an affidavit as to the correctness of the rolls and of the valuations of property made by him, and to issue and attach to the ■original roll a warrant in the form prescribed by section 38, commanding the tax collector to collect the taxes therein by sale of the assessed property. The ■charter of the city having expressly committed these duties relating to the assessment of taxes to the auditor, the city had no power to transfer them to any other person. City of Tampa vs. Salomonson, 35 Fla. 446, 17 South. Rep. 581. We do not understand that the resolution of the city council, referred to in the petition, undertook to transfer the duties of tax assessor from the auditor to the persons authorized to be •employed by the finance committee. The persons so employed were merely assistants to the auditor in making the assessment. No new office was attempted *696to be created by this resolution, nor did the resolution attempt to authorize the employee to make the assessment exclusively of the auditor. Biglow, the employee under this resolution, did not pretend to be the rightful auditor or assessor of the city. He did not attempt to oust the legal incumbent of these offices, nor did he assume to be the rightful occupant thereof. Biglow was not an officer, nor did he pretend to be an officer of the city. He was a mere employee of the-council, having and claiming no other or higher rights or duties than those of an assistant to the auditor in the matter of making city assessments of taxes. Big-low was not, therefore, an officer de facto whose acts, as such would be valid as to third persons, as was the case in the Town of Kissimmee City vs. Cannon, 26 Fla. 3, 7 South. Rep. 523. 1 Blackwell on Tax Titles, sec. 170; Cooley on Taxation, p. 251; Mechem on Public Officers, secs. 319, 321; Black on Tax Titles, sec. 93; Birch vs. Fisher, 13 Serg. & R. 208; Hawkins vs. The Intendent, etc., of Jonesboro, 63 Ga. 527; Paldi vs. Paldi, 84 Mich. 346, 47 H. W. Rep. 510; Farrington vs. New England Investment Co., 1 M. Dak. 102, 45 N. W. Rep. 191; Bailey vs. Fisher, 38 Iowa, 229; Munson vs. Minor, 22 Ill. 594. We think it is absolutely essential to the validity of a tax levy, that the assessment be made by the officer authorized by law to make it. ■ The person making the assessment must be that officer, either de jure or de facto. We do not mean to intimate that the officer must personally perform every act connected with the assessment and the-making of the tax roll. Many of these acts are of a clerical nature, involving no exercise of discretion, and having no relation to any right of the tax payer. A very large portion of these duties consists in transcrib*697ing upon the rolls the various assessments, and in calculating the amounts of taxes levied thereon. The assessor may call to his assistance the services of other-persons, whether officers or not, in the performance of all clerical or ministerial duties, and the assessment will not be invalid for that reason if the work of others is done under his supervision, or is ratified or adopted by him. But if the.assessor, either from neglect or because of other pressing duties devolving upon him, permits his assistants to perform all the duties-relating to the assessment for a whole tax year, while-he abstains from any duty connected therewith, an assessment so made will be utterly void, and it is the-duty of the courts to so declare it. The reasons are-succinctly stated by Mr. Blackwell (Tax Titles, vol. 1, sec. 168) as follows: “The statute being the authority, and the officer the agent to execute it, and no one-being empowered to do the act except the person specially designated in the law for that purpose, it follows that a stranger to the power can not execute it.. The power is conferred upon the officer, not the man. It is an official, not a personal trust. It does not rest-upon confidence, but upon official responsibility. Hence the only security of the proprietor of the estate-is the official character of the person to whom the-power is committed. This security mainly depends-upon the responsibility of the officer to the government, the sanctity of his oath of office, and his liability to those whose rights are violated by his wrongful acts. * * * The citizen is entitled to all the protection against fraud, rapacity, and abuse of authority, in the sale of his property, which official responsibility can secure.” The petition distinctly avers that the auditor or assessor performed no “duties whatever con - *698nected with the assessment of taxes for the city of 'Tampa during the year 1896;” that “the said assessment was made by the said Biglow exclusively and that the legal assessor of the city of Tampa had nothing whatever to do with the assessment aforesaid.” If these allegations are true, the assessment of petition■er’s personal as well as real property was void. Welty ■on Assessments, sec. 10; Cooley on Taxation, p: 248; Black on Tax Titles, sec. 92; Stokes vs. State, 24 Miss. 621; Munson vs. Minor, 22 Ill. 594; Ferris vs. Coover, 10 Cal. 589; People vs. Hastings, 29 Cal. 449; People vs. White, 47 Cal. 616; Farrington vs. New England Investment Co., 1 N. Dak. 102, 45 N. W. Rep. 191; Snell vs. City of Fort Dodge, 45 Iowa, 564. The allegations of the petition being sufficient to show that the ■assessment was void because made by an unauthorized person, we would ordinarily affirm the judgment without expressing an opinion upon the two other propositions stated in the beginning of this paragraph, but •as the judgment must be reversed upon another ground, and these questions will arise in the further progress ■of the case, we will proceed to consider them here.

B. Did the city of Tampa have power by contract ■or otherwise to exempt from taxation the properties of the South Florida Division of the Savannah, Florida & Western Railway Co., and the Tampa Water Works Co., and to perpetually bind itself to accept from the Tampa Bay Hotel Co. $200 per annum in full for all city taxes, without regard to the value of its property or the rate of taxation levied thereon? The plaintiff in error cites us to no authorities on this point. He plants himself upon the proposition that the exemptions were granted for a consideration, and that consequently they amounted to a contract with *699the city. But where does the city derive its authority to make such a contract? We have not been cited to-any statute of this State authorizing the city to exempt this species of property from taxation, nor to-make a contract so to do. Without valid legislative-authority, no city or town has power to bind itself by contract, either to forbear to impose taxes on particular property, or to impose them only under given limitations, or on certain given conditions. Black on Tax Titles, sec. 63; Cooley on Taxation, p. 200; 1 Blackwell on Tax Titles, secs. 110, 117.

C. Some courts have held that the intentional omission of taxable property from the assessment roll, under the tona fide belief of the assessor that such property was exempt from taxation, the effect of which omission was to increase the amount of taxes to be paid by other tax payers, would render the entire assessment void. Weeks vs. City of Milwaukee, 10 Wis. 242; Johnson vs. City of Oshkosh, 65 Wis. 473, 27 N. W. Rep. 320; Altgelt vs. City of San Antonio, 81 Tex. 436, 17 S. W. Rep. 75, 13 L. R. A. 383. Other courts hold that such omissions, even if made wilfully, or as the result of carelessness, can not-be urged to defeat taxes otherwise properly assessed;, that in such cases the officers may make themselves amenable to the law for misconduct in office, but such conduct can not “stop the wheels of government” by defeating the collection of taxes. Dunham vs. City of Chicago, 55 Ill, 357; Van Deventer vs. Long Island City, 139 N. Y. 133, 34 N. E. Rep. 774. We think tax. officers like all others are required to exercise good faith in performing their official duties. They should not use their official position, or official discretion, as. a cover for fraudulent conduct in unequally and in*700■equitably adjusting the burdens of taxation. For it is a salutary principle of law, which runs through all its branches, that fraud vitiates and annuls everything which it touches. If, therefore, tax officers intention,ally commit an illegal act with a fraudulent purpose In view, as where taxable property is intentionally omitted for an improper purpose, we have no doubt •that the entire assessment is illegal and void. If, however, the omission to assess taxable property ai’ises in consequence of a bona fide belief on the part ■of the taxing officers that the omitted property is exempt from taxation, or results from inadvertence or ■negligence, without any intent on their part to impose additional or unequal burdens upon other tax payers, the assessment will not be held to be void. Farrington vs. New England Investment Co., 1 N. Dak. 102, 45 N. W. Rep. 191; McTwiggan vs. Hunter, 19 R. I. -, 33 Atl. Rep. 5, 29 L. R. A. 526; Keokuk and Hamilton Bridge Co. vs. People, 161 Ill. 514, 44 N. E. Rep. 206; Cooley on Taxation, pp. 214-217; Black on Tax Titles, sec. 217. The petition nowhere alleges that any property was omitted from the city rolls of 1896, in bad faith or from any fraudulent purpose. In fact, the argument of defendant in error in this court is principally directed to property assessed upon the roll, and not to omissions therefrom. It is insisted that the property of the Tampa Bay Hotel Co., and of the South Florida Division of the Savannah, Florida & Western Railway Co., was placed upon the city rolls for an improper purpose, viz: to deceive the public, and make the city roll apparently valid, with no intention of collecting the taxes due upon it. It is not denied that this property was regularly and validly .assessed, and the taxes due thereon properly extended *701against it. It is not claimed that this conduct had any relation to the individual assessment against petitioner, nor that he was personally affected thereby in any other or different manner than all other tax payers whose property was assessed upon the roll for that year. If the petitioner’s assessment was illegal on that account, the entire assessment was likewise illegal. However reprehensible in morals the auditor’s •conduct may have been in assessing the property complained of, with an improper motive, he was, nevertheless, performing his official duty when he assessed it, and as the assessment, had it been made from good motives, would have been valid, because conforming to law, we can not say that it was invalid simply because it was made from bad motives. The law can not descend to an inquiry into the motives of an officer who performs an official act in strict accordance with its command. This being true, we can not hold the assessment “not lawfully made,” because the officer rightfully and legally assessed property subject to taxation, even if he assessed it with a fraudulent motive. The fact that the city collector failed to collect taxes legally assessed, or accepted a less sum than actually due in full settlement of taxes legally assessed, can not render other legal assessments amenable to the remedy given by our statute, even though such conduct be authorized by the city council, because such illegal acts do not relate to the making of the assessments, but to the collection thereof. Our statute, as will be seen by reference to its language, given in the next succeeding paragraph, does not undertake to give a remedy co-extensive with the powers of a court of equity to prevent the collection of taxes, but is coniied entirely and exclusively to “illegality” of assess-*702merits, and authorizes the court to “declare the assessment not lawfully made,” “if found to be illegal.” All inquiries upon a petition under this statute must be confined to illegalities in the assessment, and they can not be directed to other grounds of complaint against the enforcement of taxes as to which the assessment was lawfully made. Shear vs. County Commissioners of Columbia County, 14 Fla. 146.

IL Although the demurrer to the petition was properly overruled, for the reasons given in the first part of this opinion, we think the court erred in rendering final judgment upon the demurrer, without requiring proof of the allegations of the petition. It is true that the proper practice upon overruling a demurrer in ordinary cases is to enter final judgment upon the demurrer, where the party demurring declines to plead further. But this proceeding by petition is special and summary, and it is authorized as-well as regulated by the provisions of section 1542, Rev. Stat., reading as follows: “In all cases where assessments are made against any person, body politic or corporate, and payment of the same shall be refused upon allegation of the illegality of such assessment, such person, body corporate or politic, may apply to the Judge of the Circuit Court by petition setting forth the alleged illegality, and present the same, together with the evidence to sustain it, and the judge shall decide upon the same, and if found to be illegal shall declare the assessment not lawfully made.” It was not the intention of this section to permit a court in this summary manner to relieve a tax payer from his assessments upon allegations merely. It requires, the court to act upon proof. To entitle one to the benefit of its provisions he must proceed substansially *703in accordance with its terms. No proof was presented to the judge in this case. The alleged ordinances and contracts attached to the petition were not certified; many of the most important allegations in the petition were alleged upon information and belief, and the affidavit attached to the petition as to these matters merely alleged a belief that they were true. This was not the proof contemplated by the statute. It follows from these views that the demurrer was properly overruled, because the assessment was made by an unauthorized person, but the final judgment was erroneous, because entered without proof.

The judgment is reversed for further proceedings consistent with law and this opinion.