¶1The plaintiffs, as trustees under the will *366of Maria P. Codman and owners of the premises numbered 176 Tremont Street, Boston, brought this bill in equity against the owners and the lessee of the premises numbered 171 Tremont Street, to enforce a restriction upon the land of the defendants and others, which required all buildings to be set back a certain distance from the easterly line of the street. This restriction was created by an indenture made on May 29, 1857, between the owners of lots numbered 176 and 177 as parties of the first part, and the several owners of lots 171 to 175 inclusive, as parties of the second part. The parties of the first part were the five children of Henry Codman, and the parties of the second part included the predecessors in title of the present defendants who then owned lot number 171. The parties of the first part were the owners of a supposed right of entry for a breach of condition into these five lots, or either of them, if, at any time, the owner should fail to comply with a condition inserted in the deed of his lot from John Amory, dated October 12, 1811, conveying it subject to the condition that, “ All the said houses to be erected on said house lots shall be erected on a right line, . . . two feet and nine inches at least from the westerly boundary of said lots on Common street,” which is now Tremont Street. The parties of the first part in the indenture of 1857 were the owners of all rights which the grantor had under these conveyances of the five lots. By the indenture, they released all these rights to the respective persons who were then the owners of the five lots, and the parties of the second part, namely, these several owners, covenanted with the parties of the first part “ and their heirs and assigns, that none of the five houses now standing on the lots aforesaid shall be extended in any part beyond the present front line of said houses, and that no other building or buildings which may be hereafter erected instead of them, or any of them, shall in any part extend or project beyond the said front line, unless all the then owners of said five lots shall consent in writing to such extension or projection, and unless all the then owners of the estates now numbered 176 and 177 on said Tremont street shall also consent in writing thereunto.” This indenture was made for a good consideration, as between the parties of the first part and the parties of the second part, as well as between the several owners of the five lots. Under *367the deeds of 1811 there was a right of entry in the grantor for a breach of the condition in case the house to be erected on one of these lots was erected otherwise than in compliance with the condition. When the indenture of 1857 was entered into, it was evidently considered by the parties that the condition remained in force, and that a release of it might materially affect the value of the property. If the construction of the original deeds was doubtful as applied to conditions then existing, a release of all the rights under them, whatever they might be, would constitute a valuable consideration. Kerr v. Lucas, 1 Allen, 279. Dunbar v. Dunbar, 180 Mass. 170, 172. The right reserved under each of the original deeds was inheritable and devisable. Hayden v. Stoughton, 5 Pick. 528. Austin v. Cambridgeport Parish, 21 Pick. 215. It is not contended, and it could not successfully be contended, that the right of Catherine Elizabeth Codman, or of Henry Codman the younger, passed to their trustees under their respective conveyances. This right was not within the description in either deed of trust. See Rice v. Boston & Worcester Railroad, 12 Allen, 141.
¶2The contention of the defendants that their estate was not bound because the owners of the five estates covenanted “ severally and not jointly nor one for any other, for themselves and their respective successors, heirs and assigns,” is not well founded. This does not mean that the four trustees who jointly owned the defendants’ estate covenanted severally and as individual owners, and not jointly, as to this ownership; but that the several owners of the five lots covenanted severally, each as the owner of his own lot, and not jointly with the owners of the other lots, as to their respective holdings. The four trustees holding the defendants’ estate covenanted as a single owner of that property.
¶3Nor is it material that the parties of the first part then owned different interests in lots 176 and 177. John Amory Codman owned the whole of lot 177 and no part of lot 176, while the other four had formerly owned 176 as tenants in common, but Henry Codman had conveyed his one-fourth interest to trustees, and Catherine E. Codman had also conveyed her like interest to trustees. But each of them owned a beneficial interest as cestui que trust. The interest of Maria P. Codman was bound and her *368interests under the writing were protected by the act of her guardian, she then being a minor, and by her subsequent deed after she became of full age, joining with her trustees in confirming the previous execution of the indenture.
¶4It is plain from the language of the indenture that the parties intended a restriction upon each of the five lots in favor of the owners of lots 176 and 177, and their heirs and assigns, which should be for the benefit of the lots, whoever might be the owners of them. It is equally plain that equity will enforce such a restriction. It is not important to determine whether the instrument created a legal estate in the five lots, or precisely what legal estate it created, if any. It created a right enforceable in equity against all persons taking with notice of it, actual or constructive, and this equitable right is in the nature of an easement, even if it rests on no broader principle than that equity will enforce a proper contract concerning land, against all persons taking with notice of it. Whitney v. Union Railway, 11 Gray, 359, 363, 364. Parker v. Nightingale, 6 Allen, 341, 345. In the present case it plainly appears that the intention of the parties was that their respective promises should be for the benefit of the promisees as owners of the neighboring land, and of subsequent owners of these lots. Such a promise may always be enforced in equity by an owner. Peck v. Conway, 119 Mass. 546. Welch v. Austin, 187 Mass. 256. Bacon v. Sandberg, 179 Mass. 396. Ivarson v. Mulvey, 179 Mass. 141. Bailey v. Agawam National Bank, 190 Mass. 20, 23. It is not necessary that the owner should be himself the promisee. Parker v. Nightingale, 6 Allen, 341. Hopkins v. Smith, 162 Mass. 444. Evans v. Foss, 194 Mass. 513. Bailey v. Agawam National Bank, 190 Mass. 20. Collins v. Castle, 36 Ch. D. 243. Rogers v. Hosegood, [1900] 2 Ch, 388. Gibert v. Peteler, 38 N. Y. 165. De Gray v. Monmouth Beach Club House Co. 5 Dick. 329. These considerations dispose of all questions founded on the nature of the ownership of lots 176 and 177 by the predecessors of the plaintiffs in title and others.
¶5The plaintiffs are not barred by loches. The work had been done before they discovered that the erection was outside of the building line. As it was going on it was hidden from public view by the erection of a very high board fence which enclosed *369the premises along the sidewalk. Proceedings were commenced promptly after the discovery. See Linzee v. Mixer, 101 Mass. 512, 527; Attorney General v. Algonquin Club, 153 Mass. 447.
¶6ISTor have they waived their right to enforce this restriction by their failure to prosecute certain other owners who have built out certain projections in some of the higher stories of their buildings. Bacon v. Sandberg, 179 Mass. 396,399. Payson v. Burnham, 141 Mass. 547. Knight v. Simmonds, [1896] 2 Ch. 294. German v. Chapman, 7 Ch. D. 271. Mitchell v. Steward, L. R 1 Eq. 541.
¶7The change in the use of the buildings on the street since the execution of the indenture does not affect the plaintiff’s right. The importance of the maintenance of a building line may be as great when buildings are used for purposes of business as when they are occupied only as dwellings. The case of Jackson v. Stevenson, 156 Mass. 496, is very different in its facts, and the decision is not applicable to the present suit. See Evans v. Foss, 194 Mass. 513; Zipp v. Barker, 40 App. Div. (N. Y.) 1; S. C. 166 N. Y. 621.
¶8We are of opinion that this is a case in which the plaintiffs are entitled to a remedy by injunction, and that they should not be forced to accept a violation of the contract with a payment of damages. Attorney General v. Gardiner, 117 Mass. 492. Sanborn v. Rice, 129 Mass. 387. Attorney General v. Algonquin Club, 153 Mass. 447. Evans v. Foss, 194 Mass. 513; Daly v. Foss, 199 Mass. 104. The defendants proceeded with knowledge of the provisions of the indenture, and took their chances of the effect of their conduct upon the plaintiff’s rights. Upon similar facts it has been the practice of the courts to grant a mandatory injunction. Besides cases above cited see Hills v. Metzenroth, 173 Mass. 423 ; Reardon v. Murphy, 163 Mass. 501; Hamlen v. Werner, 144 Mass. 396; Bagnall v. Davies, 140 Mass. 76; Creely v. Bay State Brick Co. 103 Mass. 514; Boland v. St. John’s Schools, 163 Mass. 229; O’Brien v. Goodrich, 177 Mass. 32.
¶9 Decree for the plaintiffs.